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Studying a figure at the Worcester Art Museum

In the Conservation Lab at the Worcester Art Museum

Sign up for our e-newsletter and keep up to date with our events, projects, workshops, technical development, downloads, photos, and more. Delivered right to your inbox, the CHI e-newsletter will inform you when we release new (and free) technology, any new grants we have been awarded, where we are holding on-site training workshops for museum professionals, and news about demonstrations and other events.

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2015 E-newsletters

Your Gift to CHI Saves History! (Mid-August 2015)

Headline: Irreplaceable Cultural Heritage Saved!

Does this sound like great news?

At Cultural Heritage Imaging (CHI), we work hard to fulfill this goal every day. Now, 13 years after our founding, we need your help more than ever to support our work. Learn more and please give to CHI!

How Does Your Gift to CHI Help Save History?

Cultural heritage is precious and fragile. Historical sites and objects are under threat every day in every country of the world. Political upheaval, natural disasters, natural elements, and simple wear and tear all are putting our human history at risk. Your gift to CHI leads to breakthroughs in research, documentation, and preservation — here are some examples:

A UK archaeologist and previous CHI trainee documents the oldest human footprints outside of Africa.

Dr. Sarah Duffy, a CHI training graduate and Postdoctoral Research Associate at the University of York in the Department of Archaeology, used photogrammetry to capture 900,000 year old footprints on a beach with no time to spare! Learn more.

A conservator at the Georgia O’Keeffe Museum uses training skills and open source tools from CHI to monitor a potentially ruinous chemical reaction in paintings by O’Keeffe.

Dale Kronkright at the Georgia O'Keeffe Museum

Dale Kronkright, Head Conservator at the Georgia O'Keeffe Museum, uses RTI to identify and monitor destructive chemical changes in some of O’Keeffe’s paintings. Learn more.

A National Park Service team in New Mexico uses CHI's digital images of ancient Native American petroglyphs and Spanish and American inscriptions to monitor erosion and preserve data.

Broken rockface at El Morro National Monument

Working with the National Park Service and a team from UC Denver, the CHI team used 3D photogrammetry and RTI to image the historical inscriptions and rock art, ultimately creating a “knowledge safety net” against future losses. Learn more.

There are many more examples like these.

Your support helps us help the stewards of cultural and historic treasures everywhere, every single day. Please make a gift to CHI!

Transform Your Skills! Take Our October Classes (August 2015)

Dear CHI Friends,

Calling all archaeologists, historians, conservators, archivists, librarians, geologists, preservationists, epigraphers, and forensic examiners — and anyone else interested in acquiring the latest digital imaging techniques. Register now for our 4-day October training classes at Cultural Heritage Imaging (CHI)!

Photogrammetry Training: Tuesday, October 6 - Friday, October 9

A CHI photogrammetry class in 2015

This is your last chance in 2015 to learn how to apply photogrammetry, the practice of deriving 3D measurements from overlapping sequences of digital photographs to determine the size, shape, position, and texture of objects. The results are extremely dense and accurate quantitative data with standard digital camera equipment. Recent trainees say this about the class:

“Very informative, very technical, useful to people in different industries”
“Wonderful, amazing, and full of applicable techniques”
“In-depth knowledge sharing that is not available anywhere else”

RTI Training: Tuesday, October 13 - Friday, October 16

Shooting at a CHI RTI class

Get hands-on training in Reflectance Transformation Imaging (RTI), a core practice for creating digital representations of objects. You will leave this class able to implement the digital imaging workflow, including steps to capture, process, and view RTI digital representations. Some testimonials from previous trainees:

“Extremely informative and incredibly useful”
“Well thought-out and thorough: the small class size was a bonus for me”
“Instructors were extremely engaging and explained in a way even I could understand!”

New Working with Scale Bars Guidelines Posted on Agisoft Website

Are you already employing photogrammetry? Make sure your 3D project has accurate scale! CHI is proud to announce the publication of Guidelines for Calibrated Scale Bar Placement and Processing, a new support guide authored by us. The document is posted on the Agisoft website and it describes the main principles of calibrated scale bar use, including scale bar placement and PhotoScan Pro processing steps. Agisoft is the maker of PhotoScan Pro software, a popular software package for photogrammetric processing.

New Web Publications

CHI’s New Profile: About Us
What is our story at Cultural Heritage Imaging? Our mission has always been “We build innovative digital tools and imaging practices that save world heritage” and that remains unchanged. What we decided to do was tell the story better. To clarify our mission and our methods, we have published a new version of our About Us web page — take a look.

Coming Soon: Inscriptions and Petroglyphs at El Morro National Monument
In June Cultural Heritage Imaging began a project for the US National Park Service to capture important inscriptions and petroglyphs at the El Morro National Monument in New Mexico. Using both RTI and photogrammetry, the CHI team was able to shed light on these inscriptions and capture large-scale parts of the outdoor site for future research. Stay tuned for this new article to be posted on our web site next week!

CHI Has Been Busy! Reports from the Field (June 2015)

Dear CHI Friends,

At CHI, we get around. The CHI team calendar has been buzzing with activities, including publishing some fascinating guest blogs. Read on!

Teach and Train: Recent Workshops

4-Day Photogrammetry Training Class in San Franciso: May 2015
The CHI trainers delivered a hands-on photogrammetry class May 18-21 for participants from around the US. One highlight was imaging a very finely detailed small sculpture and seeing all the tiny parts come together into an accurate 3D model.

Computational Photography Workshop at the SAA Meeting: April 2015
It was great to see nearly 20 of our friends at the Society for American Archaeology (SAA) annual meeting in San Francisco on April 15! The CHI team offered a half-day workshop on computational photography and its application to archaeological documentation and research, including recommended software, equipment, and methods.

We are planning more training classes for the fall. Write to us at to get on the interest list.

Record and Protect: Consulting for Preservation

Petroglyphs and Inscriptions at El Morro National Monument
Among our services for hire is custom consulting. Here’s a great example: The CHI team, in collaboration with a team from UC Denver, conducted imaging work for the National Park Service (NPS) of the historically important inscriptions and petroglyphs at El Morro National Monument in New Mexico.

El Morro National Monument

RTI Shoot at El Morro

Park managers have long been concerned with protecting these artifacts from the elements of nature and other threats. They hope to preserve the works for as long as possible by assessing, monitoring and treating the inscriptions and the rocks in which they are carved. Stay tuned for RTI and photogrammetry images and results from this project!

Grave Markers and Monuments at Mount Auburn Cemetery
The CHI team visited Cambridge, Massachusetts later in June to shoot both RTI and photogrammetry of monuments and grave markers at the historic Mount Auburn Cemetery. The project involved informing local staff about what is possible in collecting this kind of data. The goal was to collect RTI imaging data from the heavily worn grave markers and baseline 3D information about sculptures that are deteriorating due to weather. The cemetery stewards are interested in using the data to monitor changes and to better enable preserving the site’s markers and monuments over time.

Reports from Our Guest Bloggers

Recently CHI has been lucky enough to publish several guest blogs from members of our community. Brief and enlightening, these reports are most definitely worth a read:

From Ravenna to Berlin: Documenting the medieval mosaic of San Michele in Africisco with RTI by Heidrun Feldmann, PhD student in History of Art at the University of Basel.
An experiment in using RTI to capture and simulate the reflection properties of a mosaic’s surface as well as document and monitor their condition.

Creating a Portable Dome-RTI System for Imaging Lithics by Dr. Leszek Pawlowicz, Associate Practitioner in the Department of Anthropology, Northern Arizona University.
The process of building a manageably small and lightweight dome to take to the field for on-site RTI imaging of lithics — including descriptions of parts and user tips! We will post part two of this blog soon.

CHI and Me: My Summer Internship and Why by Matt Hinson, a junior at the School of Foreign Service at Georgetown University.
Why Matt sought out a summer stint at CHI in San Francisco: “I have come to realize that the documentation of world heritage sites is a major component of the effort to save them.”

Capturing 15th-Century Prints with RTI by Dr. Lothar Schmitt, a post-doc in the Digital Humanities Lab at University of Basel in Switzerland.
The difficulty of recording the interaction between the light and the relief of the surface of a paste print led to using RTI to capture the subtle surface texture and layered structure of the print.

Summer greetings!

—The CHI Team

Imaging Challenge? Let CHI Experts Help (April 2015)

Dear CHI Friends,

As a nonprofit, Cultural Heritage Imaging (CHI) offers several imaging products and services for free: open source software, user guides, the latest research on imaging techniques, and a user forum. Why? We consider these fundamental to our mission: to enable digital capture and documentation of the world’s cultural, historic, and artistic treasures, now and for the future.

In addition, we offer training and some products and services for sale. These items help keep CHI going, and they also directly support our mission.

Among our services for hire is custom consulting. Here’s a great example: the CHI team will head to Mount Auburn Cemetery in Cambridge, Massachusetts in June at the behest of the Director of Preservation and Facilities there. Mount Auburn is a National Historic Landmark and one of the country's most significant cultural landscapes. The CHI team will shoot monuments and grave markers: using RTI, they will capture finely detailed surface information from heavily worn grave markers; using photogrammetry, they will collect baseline 3D information about sculptures that are deteriorating due to weather. The cemetery staff will use the data to monitor changes and to better enable stewardship plans for the site over time.

CHI Consulting

Applied Expertise: Let CHI Consult on Your Imaging Project

We are proud to offer our consulting services in the application of scientific imaging technologies, and we offer special rates for nonprofit customers.

CHI's team of experts is available for projects large and small, and our consulting services are flexible and modular. Bring us your imaging challenge, and we can help you define the consulting level that best suits your needs.

Rely on our expertise in the application of scientific imaging technologies: RTI, photogrammetry, and multispectral imaging, including:

We can provide consulting via video call, email, or in person.

CHI has provided consulting for both institutional and private clients. Read more about our consulting services. If you have questions or are interested in exploring a consulting project with us, please write to

Learn to Do It Yourself: Take Our Photogrammetry Class in May

Cultural Heritage Imaging (CHI) is offering a 4-day photogrammetry class, May 18-21, at the CHI studio in San Francisco.

For professionals in such fields as museum photography, archaeology, conservation, historic preservation, geology, and forensics, this hands-on class provides in-depth instruction on how to apply photogrammetry, the practice of deriving 3D measurements from overlapping sequences of digital photographs to determine the size, shape, position, and texture of objects. The results are extremely dense and accurate quantitative data with standard digital camera equipment. Read more about this class and enroll.

Happy Spring!

—The CHI Team

Your “Straw” is “Gold” for CHI (March 2015)

Dear CHI Friends,

Remember that fairy tale about spinning straw into gold? Most of us have stuff lying around, merchandise of little or no use to us any more but which could yield thousands of dollars to help fund our work at Cultural Heritage Imaging (CHI). If you value our mission to build and spread the use of digital tools and practices to save world heritage, you can help!

We have a new way for you to donate noncash items — as well as cash — in one single, simple interface. This is what you will see on our Donate page:

iDonate interface

Now you can contribute to CHI and get rid of excess goods at the same time. CHI can accept material gifts, such as vehicles and boats, electronics like smartphones, laptops, and tablets, and precious metals, gift cards, jewelry, collectibles, and more.

It's easy!

For example, let’s say you donate an older — but still valuable — smartphone, like an iPhone 4. Just fill in the form: we handle the rest including shipping and/or pickup.

If you donate a vehicle, the staff at iDonate (our donation system provider) will call you to arrange a pickup time, transfer the title, do all the IRS donation paperwork, and liquidate the car. All cars, running or not, will be accepted.

All cash and noncash gifts are US tax-deductible.

Please note we can accept noncash gifts from US residents only. If you are outside the US and want to donate noncash items, please contact us:

Can't make a gift? There are other ways to help CHI: spread the word about CHI on social media accounts; volunteer for a technical or marketing task; add your expertise to our discussion forums; shop on AmazonSmile — and more. See our Get Involved page for suggestions.

If you have questions about donating, click on the little gray question mark at the top of our Donate page to learn more. You can also call iDonate toll-free at 877-410-4431 or write to

And finally, please help CHI — your “straw” is “gold” to us! We hope you will help us foster digital tools and practices that save world heritage.

Thank you for all you do to keep CHI going!

— Carla, Mark, Marlin, and Casey (the CHI team)

Boost Your Skills: Learn How to Apply Photogrammetry (February 2015)

Dear CHI Friends,

You've heard about photogrammetry for 3D imaging — this spring you can finally add it to your skill set.

And speaking of sets, our photogrammetric scale bar sets are ready to ship now!

Don't Miss Our Next Photogrammetry Classes

Cultural Heritage Imaging (CHI) is offering two 4-day photogrammetry training classes in March and April at the CHI studio in San Francisco.

Tuesday, March 17 - Friday, March 20

Monday, April 20 - Thursday, April 23

Sign up for one of these classes before all the seats are taken! (Our previous photogrammetry classes have all sold out.)

In this hands-on, in-depth class you will learn how to apply photogrammetry, the practice of deriving 3D measurements from overlapping sequences of digital photographs to determine the size, shape, position, and texture of objects. The results are extremely dense and accurate quantitative data with standard digital camera equipment. The application of photogrammetry has never been more practical and useful for professionals in such fields as archaeology, conservation, geology, underwater exploration, and forensics. You will learn:

Find out more about the photogrammetry training classes and sign up!

Scale Bars for Photogrammetry: Ready to Ship

Scale bars placed around mask object Our scale bar sets are ready to ship to you! These professionally calibrated scale bars, designed by senior photogrammetry experts at the US Bureau of Land Management, are both highly accurate and very efficient for adding scale to photogrammetry projects. Each set includes 10 scale bars: 2 each of 5 sizes, to meet a variety of needs. Printed on Dibond, a tough, durable composite material, to support both indoor and outdoor use.

Learn more about this unique product on our Scale Bars page.

If you have questions not answered there, please email us at

Planning to Attend Society for American Archaeology (SAA) in April?

Going to SAA’s 80th annual meeting in San Francisco? The CHI team will present a half-day workshop, “Computational Photography Techniques for Scientific Recording and Analysis: Reflectance Transformation Imaging (RTI), Algorithmic Rendering (AR) and Photogrammetry,” at the SAA meeting in San Francisco on Wednesday, April 15. Sign up for our workshop and learn the latest information about RTI and photogrammetry.

Note: The dates of this annual meeting in San Francisco tie in nicely with the dates of our photogrammetry class in April!

2014 E-newsletters

Rita Albertson: Why I Support CHI (December 2014)

Dear CHI Friends,

I am Chief Conservator at the Worcester Art Museum in Massachusetts, specializing in painting.

My experience with Cultural Heritage Imaging (CHI) dates from 2006 when their team worked with our museum staff on the design of a prototype lighting dome for imaging precious art objects.

Since then, CHI has led training classes with our museum staff on how to apply Reflectance Transformation Imaging (RTI), a technology that has provided us with an innovative and practical solution that traditional photographic techniques could not offer.

RTI has fundamentally changed the way we document the surface texture of works of art at our museum. The practice of RTI has helped us resolve issues of attribution, dating, method of manufacture, and state of preservation on works of art, such as a stone-carved ancient Assyrian relief, a Paul Revere engraved silver cup, and a wax seal on the reverse of a 14th-century Italian panel painting.

CHI has made major contributions to the field of artistic and historic preservation, and I am grateful for their unwavering commitment to this effort over the years.

When you give to CHI, you support essential tools and practices that deeply improve the way we study cultural materials. Please give to CHI so they can continue their great work!

Capture 3D with Photogrammetry Tools and Training (December 2014)

Dear CHI Friends,

The end of the year finds us busier than ever at CHI: we’re getting ready for our two training sessions in January, preparing to roll out a new product — a set of calibrated photogrammetric scale bars — and continuing our end-of-year annual giving campaign.

Training Class Seats: Get Them While They're Hot!

Our photogrammetry class (January 20-23) is nearly sold out: only one seat left! Sign up now if you want to learn this powerful technique for deriving 3D measurements from digital photographs with demonstrable accuracy.

Our class in Reflectance Transformation Imaging (RTI) (January 13-16) is filling up, too, with some seats left. By now RTI is considered by many a core skill, well established in the cultural heritage community for its efficacy in generating digital representations with superb surface detail. Learn how to apply RTI and join over 300 of your colleagues who have already taken the training.

Can’t make it to our January classes? Sign up on our training interest list and we’ll keep you informed about our next training sessions.

Calibrated Scale Bars: Accepting Preorders for January

In late January 2015, CHI will begin shipping a new product that is unique in the world and uniquely suited to the practice of photogrammetry: a set of calibrated scale bars for accurate measurement and scientific imaging of photogrammetric data.

scale bars for photogrammetry

Our scale bars contain coded and non-coded targets and are calibrated by CHI staff to 1/10th millimeter or better accuracy. Placing them on, around, or next to your subject for photogrammetric image capture leads to extremely precise measurement in three dimensions. Learn more about the set of scale bars on our product page.

We are taking preorders and expect to ship the scale bar sets by the end of January. We will not invoice you for the scale bars until we are ready to ship them. Please see our scale bars product page and find the order forms there.

Planning to Attend Society for American Archaeology (SAA) in April?

If you are going to SAA’s 80th annual meeting in San Francisco, note that the CHI team will present a half-day workshop, “Computational Photography Techniques for Scientific Recording and Analysis: Reflectance Transformation Imaging (RTI), Algorithmic Rendering (AR) and Photogrammetry” at the SAA meeting in San Francisco on Wednesday, April 15 (see page 10 of the Preliminary Program). Sign up for our workshop and learn the latest information about RTI and photogrammetry.

Thank You to Our Donors

Our “Why I Support CHI” campaign continues as we approach the end of the year. If you have already donated, thank you so much! Our efforts to foster innovative digital imaging techniques that can be used by everyone, including under-served populations and cultures, could not continue without your help. We deeply appreciate your support!

Adam Rabinowitz: Why I Support CHI (December 2014)

Dear CHI Friends,

I am an Associate Professor and the Assistant Director of the Institute of Classical Archaeology at The University of Texas at Austin. I am also a field archaeologist with a deep commitment to open data practices and local sustainability.

I first encountered CHI’s work at a conference in 2006, and I immediately recognized the potential of the imaging techniques they were developing, in particular Reflectance Transformation Imaging (RTI). With generous funding from the Packard Humanities Institute, in 2008 I brought CHI’s experts to the National Preserve of Tauric Chersonesos in Crimea to hold a training session. After the seven-day CHI training class, staff members at the National Preserve were able to use RTI on their own to put part of the museum’s epigraphic collection online.

One of the objects we imaged was a 4th-century oath carved in marble that the citizens of Chersonesos swore to show their commitment to their democratic government. CHI has a similar commitment to the democratization of technology: they make free tools and share methods that empower communities with limited resources to apply cutting-edge digital imaging technologies. CHI is equally committed to sustainable practices and process documentation for long-term data preservation and reuse. These core values resonate deeply with me as an archaeologist.

Like me, CHI is working to make the past more accessible to everyone. Like me, CHI wants to make sure that the results of this work won’t disappear when a grant ends or the technology changes. When you support CHI, you support the preservation of our human past and guarantee it will have a future. Please give generously to CHI!

Ana Nieves: Why I Support CHI (December 2014)

Dear CHI Friends,

I am an art historian and Associate Professor at Northeastern Illinois University’s Art Department.

In January 2012, I took CHI’s excellent training class in Reflectance Transformation Imaging (RTI). I have since applied this imaging technique in the Nasca Valley, in Peru’s Department (region) of Ica, in collaboration with Peruvian archaeologist Gori Tumi Echevarría.

The sites there consist mostly of petroglyphs on poorly cemented sandstone. They are already damaged from natural processes like aeolian erosion and exfoliation. The rock art has attracted tourist traffic, and there is plenty of evidence of resulting damage, such as graffiti. Thorough documentation of these sites has become urgent before they are lost.

We use RTI to track the weathering of the rock surfaces and the destruction of the petroglyphs over the long term; with it, we can make the case for a conservation plan that would limit visits to these sites. We see RTI as critical to this documentation process: relatively straightforward to learn and inexpensive compared to other methods.

Wanting to extend RTI to Peruvians and other Spanish speakers, I volunteered to translate CHI’s user guides into Spanish (jointly with art curator Silvia Manrique), which I have used to train others in Peru. This is the chaining of knowledge that CHI intended when they set out to develop tools to save humanity's treasures.

When you support CHI, you support the power and reach of RTI. Please join me and give as generously as you can to CHI!

Jean Elliott: Why I Support CHI (December 2014)

Dear CHI Friends,

Because of my background in high-tech marketing, people wonder how I came to support Cultural Heritage Imaging (CHI) and why I serve on its Board. It comes down to three things: the team, the mission, and the impact.

I began working with CHI co-founder Carla Schroer in 1996 in Silicon Valley, where I observed her passion, intelligence, integrity, and dedication. It was exciting in 2002 to see her and her co-founder Mark Mudge channel those qualities into founding CHI.

Together they set out on a mission: to deliver innovative digital imaging tools and practices that preserve the context of important cultural sites and objects around the world. Many of these are imperiled by man-made and natural circumstances. CHI’s imaging technologies are designed to preserve these treasures in their cultural context for generations to come.

CHI has earned the right to work with some of the finest museums and scholars in the world, and it does. But CHI's impact is even greater because of its commitment to “democratizing” its approach. It makes the technologies and methods accessible to even the smallest museums and private collections around the world.

Like me, you may see supporting CHI as a form of stewardship in preserving our cultural legacy. When you give to CHI, you are enabling thousands of people to play a direct role in the stewardship of cultural heritage.

Please join me in helping CHI to continue its important work!

A Season for Giving — and Receiving Training! (November 2014)

Dear CHI Friends,

CHI is offering two training classes in January. These are practical working sessions over four days where you will work in small groups with one-on-one instruction.

We offer these classes just a few times each year, so this is your chance to absorb impressive new professional skills and take them back to your institution or practice.

Learn Photogrammetry

CHI's four-day photogrammetry training class will be held at the CHI studio in San Francisco January 20–23. Photogrammetry is an empirical practice that yields 3D photographic documentation – the highest quality image sets — with demonstrable accuracy. Archaeologists, anthropologists, classicists, epigraphers, historians, and natural scientists — anyone interested in 3D imaging and its practical applications — will find this class essential.

Take it from some of the trainees in our last photogrammetry class:

“The class greatly exceeded my expectations — both the depth of material covered and the insights from instructors and students.”

“Excellent! Very powerful technology and much more accurate than I expected.”

Find out more about the photogrammetry training class and sign up!

Get RTI Training

CHI will hold a four-day class in Reflectance Transformation Imaging (RTI) at the CHI studio in San Francisco January 13–16. RTI is a core skill that CHI has been teaching for over six years. Our RTI trainees emerge from the class with the confidence that they can apply the practice themselves.

Here is what our trainees say:

“An amazing learning experience for all levels of camera/computer users.”

“Instructors were extremely engaging, patient, and explained the complex info in a way even I could understand.”

Enroll in the RTI class now while space is still available.

Thank You For Your Support

A big thank you to all our donors in 2014! Your support has been vital to our work this year. We want you to know we appreciate your gifts: they help us continue to provide the free software, user guides, forums, and advice as you learn how to apply RTI, photogrammetry, and the other computational photographic techniques that CHI fosters.

We are now kicking off our end-of-year giving campaign, and we hope we can count on you. Unique and irreplaceable, cultural heritage is a gift from the past and a treasure we will pass on to future generations. CHI is dedicated to preserving our cultural legacy by teaching others how to capture it with computational photographic technologies such as RTI and photogrammetry.

We need your help! Any size gift is welcome. Thank you!

A Fascinating Story and New Photogrammetry Gear (October 2014)

Dear CHI Friends,

Thank you! Your response to our summer giving campaign has been encouraging. Many of you expressed appreciation for the personal statements made by our colleagues in our “Why I Support CHI” series. We will be posting more of these stories beginning in November for our end-of-year giving campaign. Meanwhile, we always appreciate your gifts to help us continue!

The oldest footprints outside of Africa: an interview with Dr. Sarah M. Duffy about the imaging of this incredible find

CHI’s latest blog is an interview with Sarah Duffy, a Postdoctoral Research Associate at the University of York in the Department of Archaeology, who was called to a beach near Happisburgh (“Hays-boro”) on Britain’s east coast in Norfolk to help document the appearance of fragile, ancient footprints that appeared there after a series of storms. Don’t miss this fascinating story!

RTI Highlight Capture Starter Kits: The Scoop on Pricing

Last month CHI announced a coming price change on our RTI kits, based on the increased cost of several of the parts. The good news is that we will hold off the new price ($370) until November 1. To get the benefit of the current price ($350) — plus shipping (and tax in the state of California) — order your kit before October 31!

Photogrammetry: New Gear and Training

CHI's 4-day photogrammetry class in October has sold out, another indication of the growing interest in this hot skill set that yields 3D documentation with demonstrable accuracy. Interested in future RTI and photogrammetry training classes? Send email to letting us know which class you are interested in so we can keep you posted.

Meanwhile, CHI is developing a set of photogrammetric scale bars, which we will sell just as we do the RTI Highlight Capture Starter Kits. See our new Gear page to learn the details as the scale bars become available, and watch for our next e-newsletter or follow us on Facebook to find out when the scale bars are ready to order.

Research in 3D: Learn Photogrammetry (August 2014)

Dear CHI Friends,

Good news! CHI has been busy arranging plans for a new 4-day training class in photogrammetry.

This subject is hot in the field of computational photography. More and more professionals in conservation, archaeology, paleontology, and cultural preservation have begun to look into this practice of deriving dense and accurate 3D surface data from photos captured with standard digital photography equipment. Our new fall class is going to fill up fast, so read on for the details and sign up!

4-Day Photogrammetry Class in San Francisco: October 6-9, 2014

The CHI team is excited to announce this class as well as the participation of photogrammetry experts Tommy Noble and Neffra Matthews of the US Bureau of Land Management (BLM), where photogrammetry has been part of the tool chest for over 20 years.

Teaming up with Tommy and Neffra, the CHI trainers will offer practical, scientific instruction in how to capture high-quality photogrammetric image sets that yield 3D documentation with demonstrable accuracy. You will leave the class with hands-on experience in how to integrate this practice into your workflow, as well as a working knowledge of the necessary imaging equipment, image capture setups, and software. Are you working on outdoor sites such as rock art panels? Interested in creating 3D animations and digital-rotatable objects that can be integrated into streaming web displays? Are you an archaeologist, an epigrapher, historian, or a natural scientist? Photogrammetric capture offers a new level of precision and documentation in all these pursuits. Sign up for our training class now!

Stepping Back, Thinking Big at the NTEN Conference in September

CHI Director Carla Schroer was awarded a scholarship to participate in the Digital Strategy track at the “Leading Change” summit hosted by the Nonprofit Technology Network (NTEN) in San Francisco, September 3-6. This conference of peers from the nonprofit world will meet to discuss their current web strategies and the steps they can take to enhance their online offerings for their constituents.

Enlightening Lightning Talks at NEH Digital Humanities Project Directors Meeting

Carla Schroer will present a 3-minute lightning talk the afternoon of September 15 at this open-to-the-public meeting in Washington, D.C. Carla will describe the goal and scope of CHI's NEH Digital Humanities Startup grant-supported project, “Data Sustainability and Advanced Metadata Management for Scientific Imaging.” The project envisions a “digital lab notebook” that will take the form of a user-friendly toolkit to document the algorithmic transformation of photographic data and the context in which the photographs were created.

Shared Knowledge Grows in the CHIforums

CHI's forums site continues to gain momentum and members. Don't miss this free source of useful and abundant information, including answers to common software problems and information on new research in the field.

Dale Kronkright: Why I Support CHI (July 2014)

Dear CHI Friends,

I am the head conservator of a small museum, the Georgia O’Keeffe Museum in New Mexico. I have also been a conservation educator for over 35 years.

After training with Cultural Heritage Imaging (CHI), I helped our team learn how to apply two CHI-fostered technologies in our conservation practice: Reflectance Transformation Imaging (RTI) and photogrammetry. We in turn share the resulting 3D images, rich in color and textural data, on our web site and in our exhibitions. The impact can only be described as “jaw-dropping” — our visitors literally can’t get enough. But the truth is we could not do any of this exciting work without the focused and dedicated team at CHI.

CHI couldn’t be more deserving of your financial support.

Why do I say this? CHI is leading on two important fronts. First, their team is doing the “heavy lifting” to refine the practices and user platforms for digital preservation, making the imaging technology more easily applicable by small, community-supported institutions like mine. Second, they have developed first-rate training classes and materials, and their classes are models of successful teaching. With these strengths, CHI is at the heart of building the critical mass needed to engage the public with the humanities using rich, interactive, image-based digital techniques.

Like me, you can help CHI continue this critically important work. When you make a gift to CHI, you are helping small institutions like mine thrive in the digital age and truly advance the preservation of our collections into the 21st century. Please, join me in making a financial contribution right now!

Tom Malzbender: Why I Support CHI (July 2014)

Dear CHI Friends,

I am a research scientist who cares deeply about the fragility of our shared cultural heritage in a volatile world. My contributions to cultural preservation are in the fields of computer vision, imaging, and 3D graphics. I am the co-inventor of Reflectance Transformation Imaging (RTI).

I have been collaborating with Cultural Heritage Imaging (CHI) since 2002, and I joined their Board of Directors in 2014. Why do I do this?

Our global cultural heritage is unique, irreplaceable, and essential to our sense of ourselves and our history on the planet. We collectively share that heritage, and we are also witnesses to the threats that prey upon it every day. When you make a donation to CHI, you are supporting the development and dissemination of practical digital imaging and preservation techniques around the world.

Like me, you may feel the strong pull of this important work. CHI has a highly successful track record of doing a lot with a little.

Give to CHI and you support the documentation and preservation of our human heritage.

Connections and Colleagues (July 2014)

Dear CHI Friends,

Since its inception in 2002, CHI has focused on spreading the word about Reflectance Transformation Imaging (RTI) and associated imaging practices. Now, over 10 years later, the practice has been adopted worldwide, with RTI and computational photography drawing more conservators, archaeologists, and cultural preservationists every year. Two recent events point to the compelling draw of this technology and CHI's place in this interesting world.

CHI's Open House

The AIC (American Institute for Conservation of Historic and Artistic Works) annual meeting was held in San Francisco this year, so CHI decided to hold an open house on the evening of May 28. Over 40 people attended: a talented crowd, including professionals from the Smithsonian, the Met, the Worcester Art Museum, and the Winterthur Museum. Attendees were friends and colleagues from out of town, and we were pleased to see our friends from several local institutions as well. Special guests included Tom Malzbender, a CHI Board member and the co-inventor of RTI; Jean Elliott, Senior Marketing Director at Microsoft and also a CHI Board member; Betsy Palmer Eldridge, a renowned Toronto book conservator who won the Keck Award from the AIC in 2010, and Vince Michael, Executive Director of Global Heritage Fund.

“All RTI, All the Time” at the Cyprus Institute: June 3-5, 2014

As part of the LinkSCEEM-2 Project, the Cyprus Institute, in collaboration with the National Center for Supercomputing Applications and the University of Illinois, hosted a 3-day workshop in Cyprus. The event brought together experts in the field of RTI and cultural heritage from Europe, the US, and the Eastern Mediterranean region to discuss the current state and future potential of RTI and its applications in cultural heritage research. Attendees presented new RTI projects, including a talk by CHI's Carla Schroer, who described the latest tools and approaches that are enabling new methods of using the same image sets captured in traditional RTIs. After the workshop, Carla posted a blog summarizing recent RTI research including reports from the Cyprus meeting.

Reaching Out (With Friends): CHI's Midyear Giving Campaign

In CHI's latest blog, “Why a Nonprofit? The Seeds of CHI,” Carla Schroer explains how the organization's nonprofit status suits its mission, while at the same time yielding a continuing need for funding. Our next few e-newsletters will be a bit different from this one, as we kick off a midyear giving campaign with a little help from our friends. Stay tuned for these special messages.

P.S. A Word About Facebook

Like many other nonprofits, CHI uses Facebook to strengthen connections with supporters and inform our colleagues of news and updates. Facebook's recent algorithmic changes and policies threaten to erode our following on the social media network. In short, if we do not “pay to play” by “boosting” our posts, we are in danger of losing touch with our supporters. We hope folks (like you, for example!) who “Like” our page will like and comment on some of our individual posts — that way you'll continue to see our content in your feed, and it helps others who have liked our page to get news from us, too.

3D Imaging: CHI Goes Deep into Photogrammetry (May 2014)

Dear CHI Friends,

Cultural Heritage Imaging (CHI) is gearing up for an exciting season with a new grant, a new area of training, and an upcoming open house for those attending the AIC 2014 conference in San Francisco. And let's not forget CHI's “April in Paris”!

NEH Grant Project Starting Up!

On March 27, the National Endowment for the Humanities announced a Digital Humanities Start-up Grant award to CHI of $60,000 for a year-long project beginning May 1: “Data Sustainability and Advanced Metadata Management for Scientific Imaging.” CHI envisions a new metadata and knowledge management methodology and a “digital lab notebook” that will take the form of a user-friendly toolkit to document not only the algorithmic transformation of photographic data, but also the context in which the photographs were created.

The project will be carried out in two case studies with groups that are already working with computational photography technologies, Reflectance Transformation Imaging (RTI) and photogrammetry. Dale Kronkright, Head of Conservation at the Georgia O'Keeffe Museum, and Adam Rabinowitz, Assistant Professor of Classics and Assistant Director of the Institute of Classical Archaeology at the University of Texas at Austin, will serve as the case study leads. They will offer recommendations to the CHI team, including software revisions for enhanced usability and the improved robustness of an archival submission tool.

Photogrammetry: Cool Training for a Hot Field

In recent years, there have been rapid advances in the techniques and tools associated with photogrammetric imaging, the practice of deriving 3D measurements (quantitative data) from overlapping sequences of digital photographs to determine the size, shape, position, and texture of objects. The application of photogrammetry has never been more practical and useful for professionals in archaeology, conservation, geology, underwater exploration, and forensics.

In mid-April, CHI delivered a sold-out pilot class in photogrammetry at the CHI studio in San Francisco for 9 invited participants. Now CHI plans to open the class to all interested parties 2 to 3 times a year.

Interested? Contact us at “training at” to be informed about the next photogrammetry class dates.

CHI at the AIC Annual Meeting in San Francisco, May 28 and 29

On Wednesday, May 28, as part of the annual meeting of the American Institute for Conservation of Artistic Works (AIC), the CHI team will deliver a workshop on computational photography from 10:00 am–5:00 pm at its studio in San Francisco.

Whether or not you can attend CHI’s AIC workshop, please join us on the evening of May 28, when CHI will hold an open house at the CHI studio for invited guests. This is a chance to mingle with conference participants and CHI staff and guests over drinks and snacks. Join us! If you are planning to attend AIC in San Francisco, and you would like to come to our open house, please send an email to “invite at”. We’d love to see you there!

The following day, on May 29 at 3:00 pm, CHI president Mark Mudge will present a talk at the AIC conference venue as part of the RATS session of the program. The talk, entitled “Accurate Measurement and the Quantification of Surface and Material Property Change Using New RTI and AR Techniques,” is based on CHI's work with Mark Drew, computer science professor at Simon Fraser University in Canada, and will examine new research that will dramatically improve the accuracy of the results generated by Reflectance Transformation Imaging (RTI) and algorithmic rendering (AR).

CHI's “April in Paris”

On April 24, at the CAA 2014 conference in Paris, France, Mark Mudge and Carla Schroer presented a talk entitled “Reflectance Transformation 3.0: Beyond Interactive Relighting.” In the talk, they described new uses for traditional RTI data, including comparing normal fields and determining normal field accuracy. Mark and Carla also enjoyed some famous French cuisine and a side trip to the National Archaeological Museum (Musée d'Archéologie Nationale) in Saint-Germain-en-Laye.

Springing Forward: New Blood, New Training, New Expertise (March 2014)

Dear CHI Friends,

Cultural Heritage Imaging (CHI) is on a roll this spring with a distinguished new member of the Board, an upcoming RTI training class, a new educational thrust into the science of photogrammetry, and an array of consulting services in computational photography.

Welcome, Tom Malzbender!

CHI is thrilled to welcome Tom as a new member of the CHI Board. A research scientist working in computer vision, imaging, and 3D graphics, Tom was formerly at Hewlett-Packard Labs where he and Dan Gelb invented Polynomial Texture Mapping, the first form of Reflectance Transformation Imaging (RTI). Tom is perhaps best known for his work imaging the Antikythera Mechanism, a project that led to the deciphering of that ancient astronomical computer. Tom has been collaborating with CHI since 2002, advising on some projects and co-authoring several papers with CHI. He continues to advance the technology and practice of image-based relighting and its practical application to archaeology, museum sciences, oceanography, and other fields. We are delighted to have access to Tom’s expertise!

Hands-on Training in RTI: April 8-11

You’ve heard about Reflectance Transformation Imaging (RTI) — this spring you can finally add it to your skill set! Sign up for CHI’s next 4-day RTI training class at the CHI studio in San Francisco, Tuesday, April 8 through Friday, April 11. Learn everything you need to know to set up, photograph, process and view RTIs. Get more information about this April class and sign up to learn RTI!

Photogrammetry: Hot Field in Conservation and Archaeology

Photogrammetry is the practice of deriving 3D measurements (quantitative data) from overlapping sequences of digital photographs to determine the size, shape, position, and texture of objects. With the spread of digital photography and the availability of mass storage devices for captured imagery, photogrammetry has never been more practical and useful, finding increased uptake by professionals in archaeology, conservation, geology, underwater exploration, and forensic work.

Now CHI is extending its training program by offering a 3-day class in photogrammetry (pilot session is already full!) to be held in mid-April at the CHI studio in San Francisco. In future, CHI plans to open the class to all interested parties 2 to 3 times a year. Contact us at if you are interested in attending a future photogrammetry class.

Consulting by CHI: Custom Services in Computational Photography

CHI provides consulting services to both institutional and private clients, with special rates for nonprofit organizations. Let CHI experts take the worry out of your specific imaging challenge. The experts at CHI have more than 30 years’ combined experience and can customize consulting services to suit your needs, including small projects. Consulting can take place via phone, email, or in person. Here are some examples of how CHI can help with your project.

For more information and other examples of CHI’s consulting services, see our refreshed Consulting web page.

New! CHI Glossary

An essential companion to your work in RTI and computational photography, CHI’s newly published “Glossary of Photographic and Technical Terms for RTI” is now available on our web site. For practiced users and newcomers alike, the glossary is a compendium of words and phrases associated with the domain of RTI and related imaging practices. It contains definitions of photographic terms, computer graphics and computer vision terms, file formats, as well as newer terms related to keeping a process history of RTI work. We adapted the definitions for RTI users, and we also included a few notes and recommendations on photographic settings. Read more in our blog.

Come Join Us at the AIC Annual Meeting in May 2014!

On May 28, as part of the annual meeting of the American Institute for Conservation of Historic and Artistic Works (AIC), the CHI team will offer a workshop on computational photography and its application to conservation documentation and research. The workshop will be held from 10:00 am to 5:00 pm at the CHI studio in San Francisco. Come join us!

At 3:00 pm on May 29, CHI president Mark Mudge, along with Mark Drew, computer science professor at Simon Fraser University in Canada, will present a talk as part of the RATS session in the program. This talk examines new research that will dramatically improve the accuracy of the results generated by Reflectance Transformation Imaging (RTI) and Algorithmic Rendering (AR).

CHI at MIT in February 2014

On February 27, Carla Schroer of CHI presented a talk at Hayden Library at the Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts. Hosted by the MIT Libraries’ Curation and Preservation Services Department, the talk was free and open to the public. Carla described the latest robust new empirical image capture and analysis tools: Reflectance Transformation Imaging (RTI), Algorithmic Rendering (AR), and Structure from Motion (SFM) generation of textured 3D geometry.

CHI at Eastern Analytical Symposium & Exposition (EAS) November 2013

Last November, at the meeting of the Eastern Analytical Symposium & Exposition (EAS) in Somerset, New Jersey, Mark Mudge and Carla Schroer presented 2 talks in a two-part session entitled “Analytical Imaging for Cultural Heritage.” They described new research from Princeton University, Simon Fraser University, and the Georgia O’Keeffe Museum that demonstrates how the techniques associated with computational photography can be used to track changes in object surfaces. They also explored the necessity for transparent evaluation of scientific digital representations, or “digital surrogates,” that can reliably serve as digital stand-ins for subsequent scientific or scholarly examinations.

Thank you to Scott Verges!

We would like to thank outgoing board member Scott Verges. Scott has served on the CHI Board since 2008, and we really appreciate his time, effort, ideas, and enthusiasm! Thanks, Scott!

2013 E-newsletters

Help CHI + New RTIViewer (December 2013)

Dear CHI Friends,

The end of 2013 is fast approaching, and we need your help!

Annual Giving Campaign Ends December 31, 2013

CHI relies on the support of people like you who care about cultural heritage, historic sites, and natural history collections. Your generous support by December 31 will allow us to continue to empower and grow this community until people all over the world can document and share humanity’s treasures today and in future generations.

We are happy to report that digital imaging tools and methods developed by CHI and our worldwide collaborators are in use on every continent on Earth. Yes, even in Antarctica, a conservator is using Reflectance Transformation Imaging (RTI) to examine artifacts from the doomed Scott expedition to the South Pole.

RTI tools fostered by CHI are transforming the field of fine art conservation. The adoption of these tools has spread through the museum community, and we are seeing increased uptake in archaeology projects.

To date CHI has directly trained over 300 museum professionals, archaeologists, and researchers from more than 70 institutions in robust scientific digital imaging techniques. In turn, many of them have taught others. This “teach a person to fish” philosophy has fostered a growing, thriving user community. Online, the free CHIForums is growing, a discussion site where users share the latest digital imaging advancements and help each other improve their imaging skills.

Do You Use RTI? Will You Help Support It?

This year our Annual Giving Campaign coincides with the release of new and improved RTI software.

We need your help to continue offering RTI software updates, user guides, user forums, videos, and other materials to the cultural heritage community.

When you donate to keep RTI software and guides updated and available, you are also supporting cultural heritage preservation, museum conservation, and natural science and forensics research—all the fields in which RTI has become an important imaging technique.

How to Donate

Please make a tax-deductible (in the USA) donation to Cultural Heritage Imaging by December 31, 2013. All contributions of any amount will help. As a small nonprofit organization, we need—and deeply appreciate—your financial help. Thank you!

More Ways to Help CHI Thrive

In addition to donations, there are many ways you can help CHI succeed. Please pass on this email to others who might be interested in our work; “Like us” on Facebook; introduce our work to colleagues who could take advantage of the tools, training, and services we provide; become a CHI volunteer. Read more about the ways you can get involved.

New RTIViewer Release 1.1

We are pleased to announce an update to the free and open source RTIViewer software.

RTIViewer 1.1 is now available for download on the CHI web site. This latest release of the viewing software includes these new features:

New RTIBuilder 3.0 Release on the Way

We are also working on a major new release of RTIBuilder. Your donation makes possible our updates to the software, user guides, and other free materials.

Thank you and best wishes from the CHI Team!

Summer 2013

Dear CHI Friends,

The team at Cultural Heritage Imaging (CHI) wishes you a happy summer solstice and invites you to celebrate the latest advances we've made in the world of reflectance transformation imaging (RTI) and preservation of cultural heritage worldwide. CHI has added major instructional updates to the RTI User Guide, uploaded informative new videos, and reached out to the Spanish-speaking world with translations of our user guides.

User Guide Update: Working With Light & Shadow

CHI has posted a major update (RTI: Guide to Highlight Image Capture, Version 2.0) of the original v1.1 user guide, describing the camera, lighting, software, object and reflective sphere setup, and capture sequence process. The enhanced guide contains new features, more detailed descriptions, and more how-to illustrations.

New Video Instruction Tools Available

In another stride to aid users in the capture technique, CHI has posted a new how-to video (Light Positioning for Horizontal RTI Data Capture) describing the basic concepts and steps for light positioning in a horizontal RTI data capture. An additional video, Light Positioning for Vertical RTI Data Capture, is in the works.

Nuevo! RTI Materiales en Español!

Thanks to the translation efforts of volunteers Ana Nieves and Silvia Manrique, CHI now offers Spanish speakers two RTI user guides in Spanish: Imágenes por Transformación de Reflectancia: Guióa Para La Captura de Imágenes Utilizando Luces Portátiles, Versión 1.1SP (RTI capture guide) and Guía Para El RTIViewer, Versión 1.0.2SP (RTI Viewer Guide). CHI will post more Spanish translations as they become available — check CHI's Spanish translation page for future additions of Spanish language material and links to RTI resources in Spanish.

2013 International Rock Art Congress (IFRAO)

CHI’s Carla Schroer and Mark Mudge presented a workshop at the IFRAO 2013 conference (International Rock Art Congress, hosted by the American Rock Art Research Association (ARARA) in Albuquerque, New Mexico) on May 30. In the workshop, presented in two one-hour segments, they examined the robust new empirical capture and analysis tools RTI, algorithmic rendering (AR), camera calibration, and image-based structure from motion (SFM) generation of textured 3D geometry. While attending IFRAO 2013, the CHI team took a field trip to capture some data at the Petroglyph National Monument, and they posted photos on the CHI Facebook page, as well as a blog entry about the experience.

CHI's RTI Discussion Forum Community Grows

CHI’s free discussion forum site is a resource where RTI and photogrammetry users can share their questions, discoveries, and problems-to-be-solved as they use the technology. The forum has been rapidly expanding with new users and new content. There are now more than 125 members, and there have been more than 500 postings to the forum since its launch earlier this year. The forum is a great way for RTI users to stay up to date and get advice as they apply the technique.

The Impact of CHI’s 21st Century Museum Professionals (21MP) Grant

The 21MP training grant program, generously funded by the Institute of Museum and Library Services (IMLS), has come to a close. In addition to enabling CHI to deliver the 10 training workshops supported by the grant, the funding supported the continuing development of RTI software and user materials and the launch of a free, online RTI community forum where members can share information as they use the technology. See also CHI’s new image galleries on Flickr, including photos taken on site at the training sessions at the four regional host museums and at the six ANAGPIC schools (Association of North American Graduate Programs in the Conservation of Cultural Property).

Please Help Support the Software & User Materials CHI Delivers

If you value RTI software and user guides, please consider donating to Cultural Heritage Imaging. As a small nonprofit organization, we deeply appreciate and need your help to continue our mission.

March 2013

Dear CHI Friends,

The first few months of 2013 have been interesting for Cultural Heritage Imaging (CHI), to say the least! We defended our fabulous and popular discussion forum from cybercriminals who tried to hack into it and use it for their nefarious plans. CHI also participated in a unique digital heritage project with the Georgia O'Keeffe Museum, expanded our imaging techniques into the forensic field, and collaborated with archaeologists and heritage professionals at a variety of gatherings. We couldn't have done it without the wonderful help and support you give us!

Shout Out To Our Supporters Of 2012

CHI is grateful to everyone who has supported Cultural Heritage Imaging this past year—whether you worked directly with us, participated in a CHI training class, joined the CHI discussion forum, “liked” us on Facebook, sent us a donation, and/or offered any other kind of support for CHI. As a small nonprofit organization, we deeply appreciate and need your help to continue our mission.

Intrepid CHI Team Defeats Hackers and Restores Our Discussion Forum!

CHI is happy to provide a free discussion forum site where our users can share their questions, discoveries, and problems to be solved while using Reflectance Transformation Imaging (RTI) technology. As some of you know, our forum was hacked by intruders late last year, which led to a temporary outage. The good news is we have resolved the problem and removed the vulnerability. We have migrated the existing forum content to a professionally hosted site run by the company that creates the forum software we use.

What you should know:

Thanks to all of you who stuck with us through this frustrating period while we reconstituted the forum. You can read more here.

The CHI Team Is Part of an Emerging Science at Global Gathering

At the WAC-7 World Archaeological Congress in January 2013 by the shores of the Dead Sea in Jordan, CHI’s Mark Mudge and Carla Schroer presented two talks on the advances in robust new digitization tools from the emerging science “computational photography”:

Documenting Georgia O'Keeffe's Historic Homes

In an article, “Comparing Digital Photogrammetric Methods for Preservation Documentation,” the National Center for Preservation Technology and Training (NCPTT) describes how their 2011 grant helped fund a project run by the conservation department at the O’Keeffe museum in which CHI participated. The effort began by documenting the condition of Georgia O’Keeffe’s residences in Abiquiu and Ghost Ranch, New Mexico and objects in the museum collection using 3D digital photographic technologies: RTI and Photogrammetry. In addition to the article on the NCPTT website, the project put up a very useful blog site with articles, video, how-to documents and lots of useful info about their experience and advice after undertaking this work.

Petroglyph Goats Do Roam—CHI Shares Technology Insights at Summit

CHI's old friend—the leaping goat petroglyph from Portugal—accompanied them to the Presidio of San Francisco to be an RTI example at the NCPTT's 3D documentation summit in Summer 2012. A video from that summit is being made available on the NCPTT web site, and the talk delivered by Carla Schroer and Mark Mudge is available there now (along with the goat!).

CSI San Luis Obispo—CHI Trains Forensics Specialists

In December 2012 at the San Louis Obispo Sheriff’s office, and in February 2013 at the CHI studio, CHI delivered hands-on training classes in RTI for forensics professionals. When RTI is applied in the field of forensics, it can dramatically improve the visualization of textural evidence, such as footprints, tire impressions, tool marks, fingerprints, ink crossovers, and obliterated serial numbers. CHI looks forward to more opportunities to work with the forensics community.

21st Century Training Enters Final Phase

Cultural Heritage Imaging has finished the training grant program generously funded by the Institute for Museum and Library Services (IMLS) 21st Century Museum Professionals (21MP). Collaborators from industry, higher education, computer science, and the museum community all supported the training program. CHI has achieved all of the project’s second-year objectives, including planning, organizing, and delivering the final 4 training classes out of the total of 10 supported by the 21MP grant.

Training evaluation comments by participants were universally positive regarding the value of RTI for museum research, public education, and art conservation. Trainees praised the knowledge of the CHI team, the organization of the class, and the quality of the teaching.

In the final weeks of the grant, CHI is working to complete updates to its user guides and other training materials for users to aid in the adoption of RTI.

2012 E-newsletters

December 27, 2012

“As 2012 ends, a heartfelt thank-you, an opportunity, and a gentle reminder”

Dear CHI Friends,

As the year draws to a close, we'd like to thank everyone who has supported Cultural Heritage Imaging this year—whether you worked directly with us, participated in a CHI training class, joined the CHI discussion forum, “liked” us on Facebook, sent us a donation, and/or offered any other kind of support for CHI. As a small nonprofit organization, we deeply appreciate and need your help to continue our mission.

RTI Training Class Discount

We hope you and your colleagues can take advantage of an early registration discount of $200 for our February 11-14 RTI training class if you sign up by January 11, 2013! The regular price is $1695 per person for the 4-day class, but it will be $1495 if paid by January 11. Learn more…

Even Small Donations Help CHI

It's not too late to donate to CHI! Our 2012 annual giving campaign is still underway. By donating even small amounts of money to CHI, you can help save, preserve, and share humanity’s art, cultural heritage, and natural history. Learn more…

Thank you for your support and Happy New Year!

—Carla, Mark, Marlin, and Casey (the CHI team)

December 2012: Annual Giving Campaign

Dear CHI Friends,

Are you a history buff? Are you an art lover; a museum visitor; a natural scientist or a humanities scholar? Are you a parent? If so, here’s a way you can help save, preserve, and share humanity’s art, cultural heritage, and natural history.

Cultural Heritage imaging (CHI) is a 10-year-old nonprofit corporation. CHI fosters an international collaborative community. Its founders understood that this community was needed to help drive the development and widespread adoption of robust digital tools to document and study our world scientifically. The tools and methods CHI develops are made possible by this worldwide charitable collaboration of experts in many cultural and scientific disciplines, working alongside leading digital scientists in machine vision, remote sensing, and computer graphics. As an independent charity, insulated from academic and institutional rivalries, CHI has successfully built collaborations between leading scientists, scholars, and institutions based on “pulling on the same oar” for the public good.

Your charitable gift enables CHI and its collaborators to develop tools and equip cultural heritage and natural history practitioners, museums, and other educational institutions, and the interested public with the latest in robust, photography-based, digital imaging technologies and practices. With your contribution to CHI, you are directly saving humankind’s cultural and natural history treasures. You are also empowering increasing numbers of people around the world, real boots on the ground, to build humanity’s digital legacy.

CHI’s Impact

At over 40 leading museums in North America, and in a quickly expanding number of museums across the world, tools fostered by CHI are used in conservation labs, museum/public outreach, on-site exhibits, and remote, user-interactive web displays of museum content. These tools, built by CHI and their worldwide network of software collaborators, are in use on six continents. These museums include the Smithsonian Institution, the Metropolitan Museum of Art, the Museum of Modern Art, the Los Angeles County Museum of Art, the Cleveland Museum of Art, the Fine Arts Museums of San Francisco, the Egyptian Museum in Berlin, the British Museum.

At all of the art conservation graduate schools in North America, CHI has trained both faculty and graduate students, who are now using a new generation of digital imaging tools. This means that all new conservation graduates will begin their careers with knowledge of the rapidly developing digital imaging power of 21st-century technology.

In Peru, historians trained by CHI use digital tools to scientifically capture, analyze, and share the surface-feature shapes and colors of ancient petroglyphs at the Nasca Valley site.

At the Tauric Preserve of Ancient Chersonesos, Ukraine, CHI-trained Ukrainian stone conservators and 20 of their colleagues all wanted a hand in the robust digital documentation of a 3rd-century BCE national treasure, a stone engraved by ancient Greek inhabitants of this community. The stone contained an oath, affirmed by all in the population, pledging “I will not throw down the democracy.” At the same site, the Ukrainian conservators deciphered the answer to a 100-year-old mystery surrounding an expensive, imported re-carved grave marker — the name of its original owner.

CHI Is Unique

The fact that CHI is an independent charity, working solely for the public good, leverages your donation. Often, within the context of this work for the public good, CHI collaborators heavily discount their fees, and/or contribute volunteer labor.

The software tools and do-it-yourself user guides CHI develops are distributed for free. In today’s budget-conscious environment, for all but a few wealthy organizations, there are many outstretched hands for only a small and shrinking pot of available funding. CHI develops its tools and methods explicitly so that they can be used by institutions and groups with limited budgets and limited technical expertise all over the world.

The software tools are open source, so that anyone can get the programming code for the software. This means that anyone can work on the software to improve it or adapt it for a given application.

CHI tools capture the scientifically necessary information of the digital imaging process that aids long-term preservation and enables the reuse of that scientific data in the future.

By contributing to CHI, you are doing your part to preserve irreplaceable art and natural treasures for both your children and the children of the future. This investment dividend is multiplied by today’s intensive digital image research, which will produce ever more powerful ways to mine this scientifically preserved knowledge of ourselves, our ancestors, and our world.

CHI Needs Your Help

As a person concerned with humanity’s legacy, your donation to CHI is an investment in our own and future generations. For people in the US, this is a tax-deductible charitable contribution. Please donate $5, $20, $50 or any amount that you can manage to help us continue this work. Wherever you are, you can donate securely via credit card on our Donate page. Sending us a check works, too. Thank you!

October 2012

Dear CHI Friends,

Autumn is upon us—the Cultural Heritage Imaging (CHI) team has planted a garden of great ideas and initiatives and now we are harvesting the benefits big time! Please read on to discover our latest achievements and future events to look forward to.

CHI’s New Discussion Forums: Join the Conversation!

This conversation is for you: CHI is delighted to announce the release of our new free forums site:

When you create a free account for this forum, you are joining the growing community of Reflectance Transformation Imaging (RTI) users all over the world. The forums are designed to be a learning center where you can look for both news and advice: How are museum conservators, computer scientists, natural scientists, photographers, and other related professional groups using RTI? What problems are they solving? What challenges are RTI users encountering in their projects? You and your colleagues can use the forums to share your questions, insights, and issues to gain a more complete understanding of the technology and its practical applications. CHI is grateful to the Institute of Museum and Library Services (IMLS) for our 21st Century Museum Professionals grant, as a small portion of that funding helped us get the forums going.

October Training Classes in Berlin

The CHI training team (Mark Mudge, Carla Schroer, and Marlin Lum) is heading to Berlin, Germany for two back-to-back RTI training classes at the Staatliche Museen. These classes are sponsored and hosted by the Excellence Cluster Topoi, a research network with a focus on the study of the ancient world, and the Staatliche Museen zu Berlin, where the classes will be held. The training classes are full, but there are also two workshops and a lecture that are open to the public.

Forensics Training in December

Marking a new direction in CHI training opportunities, the CHI team will conduct their first class for forensics professionals, hosted by the Sheriff’s Office in San Luis Obispo, California from December 3-7, 2012. This five-day training class is appropriate for anyone involved in photographing evidence, including forensic photographers, footwear and tire-track examiners, tool-mark examiners, trace-evidence analysts, questioned-document examiners, and crime-scene investigators. The class opens with an optional eight-hour introductory module covering photography basics, best practices, and legal concerns for RTI. The remaining four days focus on the hands-on application of RTI: how to take RTI images, compile RTI files, and disseminate these for forensic use.

New Four-Day RTI Training at the CHI Studio in February

CHI is planning a new four-day training in Reflectance Transformation Imaging, February 11-14, 2013. Visit the training page for updates and registration.

National Archaeology Day

October 20 is “National Archaeology Day” (, sponsored by the Archaeological Institute of America (AIA,, “a celebration of archaeology and the thrill of discovery.” Every October the AIA and archaeological organizations across the United States, Canada, and abroad present archaeological programs and activities for people of all ages and interests.

Cultural Heritage Imaging is a tax-exempt 501(c)(3) company. Donations are tax-deductible.

Summer 2012

Dear CHI Friends,

The summer solstice has arrived and Cultural Heritage Imaging (CHI) is taking advantage of all the extra daylight to whip up a full plate of activities and accomplishments. The latest news is here for your review!


CHI President Mark Mudge and Director Carla Schroer are spending the final week of June with staff and interns at the Georgia O'Keeffe Museum to help them kick off an eight-week O'Keeffe Museum Conservation Program Summer Preservation Project. The CHI team is helping O'Keeffe project members learn about Reflectance Transformation Imaging (RTI) and photogrammetry. Check the blog at for more project updates as the summer progresses.


CHI President Mark Mudge, Director Carla Schroer, and Imaging Director Marlin Lum present a talk and a demo at the NCPTT 3D Digital Documentation Summit taking place in San Francisco, July 10-12, 2012. The talk, entitled “Advances in computational photography techniques for cultural, historic, and natural history materials” surveys the latest developments in Reflectance Transformation Imaging (RTI), Algorithmic Rendering (AR), camera calibration, and methods of image-based generation of textured 3D geometry. The demonstration walks viewers through how RTI and AR are accomplished with readily available photographic gear. Visit CHI's Events page for links and other updates.


IMLS-Funded RTI Training. CHI held two four-day training classes at Buffalo State (January 17-20, 2012) and at the Smithsonian’s Museum Conservation Institute (March 5-8, 2012). These are the seventh and eighth training sessions out of 10 sponsored by a grant from the Institute of Museum and Library Services (IMLS)'s 21st Century Museum Professionals Program. The IMLS grant funds RTI training for all North American graduate programs in conservation, as well as several regional training sessions open to museum professionals.

CAA 2012 Conference. In late March, Mark Mudge presented a keynote at the CAA 2012 Plenary session entitled: “Computational photography’s emergence and the ascent of digital image transparency” — view the video of his keynote. At this same conference Mark Mudge and Carla Schroer presented a workshop on Computational Photography and a paper entitled “Advances in the Computational Photography Tools: Reflectance Transformation Imaging (RTI) and Algorithmic Rendering (AR).”

Society for the Preservation of Natural History Collections (SPNHC). In mid-June, Mark Mudge and Carla Schroer demonstrated how RTI has the potential to revolutionize the documentation, treatment, and research of natural history and art museum collections. They also gave an overview of the inexpensive and easy-to-learn image capture methodology and image processing based on RTI open-source software. Attendees also saw examples of the resulting RTI images using the RTIViewer, a viewing and analysis tool. The conference was hosted by the Yale Peabody Museum of Natural History at Yale University.

Stanford Research Institute (SRI), Artificial Intelligence Center (AIC) Seminar. Carla Schroer spoke at SRI AIC's seminar series on robust new imaging tools from the emerging science known as Computational Photography. The common feature of the computational photography imaging family is the purpose-driven, selective extraction of information from sequences of digital photographs for use with a wide range of cultural and natural history materials and associated research.

New CHI Published Article. Carla Schroer published an article in the February/March 2012 issue of the Bulletin of the American Society of Information Science and Technology. Entitled “Museum Informatics: Something New, Something More,” the article highlights CHI's work in art conservation using RTI technology. Among other examples, the author cites a microscopy study during an RTI training session at the Straus Center for Conservation and Technical Studies of the Harvard Art Museums. In that study, the participants examined makers' marks on gold and silver objects. This study was part of a 2011-2012 training project sponsored by the IMLS 21st Century Museum Professionals Program.


Visit CHI on Facebook to stay in touch and get the latest news and updates. Don't forget to like us, comment on what's going on, and add us to your Facebook world too! Use the buttons at the top of this e-newsletter to like, retweet, or share our news with your friends on Facebook, Twitter, or Linked In. Go to the CHI blog for some spectacular new postings by Marlin Lum and guest bloggers who are using CHI techniques in a variety of amazing projects. Let us know what you think!

Cultural Heritage Imaging is a tax-exempt 501(c)(3) company. Donations are tax-deductible.

January 2012

Dear CHI Friends,

Cultural Heritage Imaging (CHI) is accelerating to light speed in the new year with a redesigned web site, new web pages, contributions to new books, a new reflectance transformation imaging (RTI) kit for sale, and much more. Read on to find out what we've been up to.


Check out CHI's beautiful new web site at! There's lots of interactive content and updates—for an overview of what's new, read CHI Director Carla Schroer's blog entry announcing the new and improved site features. In addition to the links to great new content in Carla's blog, don't miss the new rock art page—a perfect example of how the redesigned site leads you to all subject-relevant content.


Visit CHI's new Publications page for links and other updates. Here are a few highlights:

Companions To Rock Art. August 2012 is the publication date for the latest title in Wiley-Blackwell's Companions to Anthropology Series, A Companion to Rock Art. The CHI team and their collaborators contributed a chapter to the section, “Rock Art As Digital Heritage: Advances in Photo Enhancement Technology and Digital Archiving.” The chapter is called “Robust, Scientifically Reliable Rock Art Documentation From Digital Photographs.”

Visualization In Research. CHI President Mark Mudge is contributing a chapter to a February 2012 book from Ashgate, Paradata and Transparency For Virtual Heritage. Mark's chapter is “Transparency For Empirical Data.” This new title is part of the Digital Research in the Arts and Humanities series.


Get Into Training. CHI's training sessions are growing in popularity—the latest one sold out, but there's still time to get into the next one in San Francisco on April 24-27, 2012. Visit CHI's Training page for details about the types of classes offered and some of the distinguished alumni from around the world who are CHI graduates!

Get Into the Field, Lab or Workshop. Kick-start your digital cultural heritage projects with CHI's new RTI Highlight Capture Starter Kit. The CHI team has assembled everything you need to create your own interactive RTI media—just add a basic camera, tripod, and some accessories and you are good to go! Learn how to use the kit at one of CHI's training sessions, or download helpful documentation and media from CHI's Do It Yourself resource page. Let us know how your project goes—connect to us via social media and keep us in the loop!


Visit CHI on Facebook to stay in touch and get the latest news and updates. Don't forget to like us, comment on what's going on, and add us to your Facebook world, too! We hope you'll like, retweet, or share our news with your friends on Facebook, Twitter, or LinkedIn.

Cultural Heritage Imaging is a tax-exempt 501(c)(3) company. Donations are tax-deductible.

2011 E-newsletters

Autumn 2011

Dear CHI Friends,

Summer 2011 has been a period of great change and accomplishments for Cultural Heritage Imaging (CHI). In a single year, we have completed half of the training for our two-and-one-half year federally funded museum professionals program.

Institutions and individuals we have trained are moving along with their reflectance transformation imaging (RTI) projects and have begun posting the results on the web, including the Worcester Art Museum, the Smithsonian, and the Fine Arts Museums of San Francisco.

CHI welcomes a great new collaborator and is saying good-bye to another supporter whose efforts we really appreciated and built on. Please read on for updates and links to our latest news.

IMLS-Funded RTI Training 50 Percent Complete

In September, the CHI team trained art conservation professionals at Queens University, Ontario, Canada, in RTI techniques. Researchers there had already been experimenting with RTI on reverse glass paintings as documented in this CHI blog entry. The Queens training is the fifth program undertaken for the Institute of Museum and Library Services (IMLS)'s “21st Century Museum Professionals Program.” The IMLS grant funds RTI training for all North American graduate programs in conservation, as well as several regional training sessions open to museum professionals.

Earlier in the year, CHI trained the NYU Institute of Fine Arts Conservation Center—in addition to CHI's photo blog posting and Flickr gallery about the four-day event, NYU has posted a great article describing the experience. Additional training programs occurred at the Harvard Art Museums Straus Center for Conservation and Technical Studies, the Worcester Art Museum, and the San Francisco Museum of Modern Art (SFMOMA). SFMOMA added workshop photos to Facebook.

RTI in Action

Seeing Red. The Worcester Art Museum jumped right into the classics after acing CHI's RTI training back in 2008, and is using the advanced imaging techniques to study surface details on a Greek Attic red-figure vase in their collection. Read about what they found in their CHI blog entry.

The Fine Arts Museums of SF also used RTI for some high-end imaging of a red-figure object and posted a blog entry about the amazing results.

Main Squeeze. The Smithsonian Institution's Museum Conservation Institute (MCI) also put their 2009 CHI RTI training to good use and made RTI images of 400 ancient “squeezes”—wet paper pulp pressed into ancient inscriptions, such as those found on stone walls in the Near East. The squeezes make mirror image impressions of the writing that can be taken away from where the inscriptions reside and studied. Read more about the Squeeze Imaging Project and CHI's RTI contribution, which has been implemented by the MCI's Imaging Studio.

Farewell and Bonjour

Best Wishes. CHI bids a fond adieu to Dr. Elizabeth Peña, our hard-working former Executive Director. Elizabeth has accepted a position as Interim Director of Museum Studies at John F. Kennedy University in Berkeley, CA. Goodbye, good luck, and thank you Dr. Peña—CHI could not have made our IMLS-funded RTI training project happen without you!

A Big Hello! Corey Toler-Franklin, PhD, is a Postdoctoral Fellow at Yale collaborating with CHI on the National Science Foundation (NSF)-funded Collaborative Algorithmic Rendering Engine (CARE) Project. Corey will contribute details for the “digital lab notebook,” or process history aspects of this project. To learn more about Corey, visit

Get CHI Updates On Facebook

Visit CHI on Facebook to stay in touch and get the latest news and updates. Don't forget to like us, comment on what's going on, and add us to your Facebook world too!

Cultural Heritage Imaging is a tax-exempt 501(c)(3) company. Donations are tax-deductible.

April 2011

Dear CHI Friends,

Cultural Heritage Imaging (CHI) is focused on making reflectance transformation imaging (RTI) training available to everyone. We've recently conducted RTI training sessions for conservation staff at two renowned institutions in New York City. Applications are available now for museum professionals wishing to receive RTI training sponsored by a new federal grant program. CHI also plans to offer additional training opportunities this summer.

CHI Training in the Big Apple

Metropolitan Museum of Art conservators learned RTI techniques recently, as described in a CHI blog entry about the four-day experience. Later this spring, students at the NYU Institute of Fine Arts Conservation Center also participated in a four-day RTI training program funded by CHI's grant from the Institute of Museum and Library Services (IMLS). See the students and the CHI team in action in this photo blog posting and Flickr gallery.

Apply For Free RTI Training

CHI is accepting applications now from museum professionals who would like to take the tranining program that staff at the Metropolitan Museum of Art and NYU students recently used to learn about RTI and how it can help their work. Visit the “Imaging Technology Pathways for Museum Professionals” (IMLS) project page to learn more about this “21st Century Museum Professionals Program,” which is funded by the IMLS. Review CHI's grant application page to download an application and find out where the RTI training will take place.

More RTI Training June 7–10

Check CHI's Training page for more info on the next RTI training in San Francisco. Apply now for this exciting four-day program which offers engaging lectures, demonstrations, and hands-on sessions where small groups work together on RTI projects.

Get Involved With CHI On Facebook

Visit CHI on Facebook to stay in touch and get the latest news and updates. Don't forget to like us, comment on what's going on, and add us to your Facebook world too!

Cultural Heritage Imaging is a tax-exempt 501(c)(3) company. Donations are tax-deductible.

February 2011

Dear CHI Friends,

The Cultural Heritage Imaging (CHI) team is already making the most of 2011! We've released a great new FREE technology tool, trained museum staff at one of the world's most prestigious institutions, appeared in leading cultural heritage publications, and taken steps to share our knowledge at upcoming conferences and events.

FREE Viewer Available For Download

CHI is proud to announce the first public release of our new reflectance transformation imaging (RTI) viewer! Work on this viewer has been funded in part by a generous grant from the Institute of Museum and Library Services (IMLS). The new RTIViewer was created by the incredibly talented team at the Visual Computing Laboratory of the Italian National Research Council's (CNR) Institute for Information Science and Technology (ISTI). CHI President Mark Mudge co-authored a paper about the new viewer with ISTI and CNR staff for the Journal on Computing and Cultural Heritage (JOCCH). Visit JOCCH to learn more about the paper, “Dynamic Shading Enhancement for RTI.”

Download RTIViewer 1.0.2 for Windows or Macintosh operating systems from CHI's RTIViewer page. On the same page, you can download a RTIViewer User Guide and sample files of ancient rock art and papyrus artifacts to use with the viewer. Please try it out and let us know what you think—we welcome your comments and support.

CHI Featured in New Online Archaeology Magazine

Check out a great article, “Cultural Heritage Imaging: Digital Pioneers in Archaeological Preservation,” in Electrum Magazine, a new online publication about archaeology and “why the past matters.” The Electrum article is a thorough overview of CHI's RTI research, starting with the Stanford Alpine Archaeology Project in Switzerland and continuing right up to the present with the Fine Arts Museums of San Francisco using RTI to study Japanese woodblock prints in new ways.

The Metropolitan Museum of Art Learns RTI With CHI

The CHI team recently traveled to the Metropolitan Museum of Art in New York to train conservators in RTI techniques by creating images of objects from the museum collections. CHI Executive Director Elizabeth Peña and CHI Imaging Director Marlin Lum posted a blog entry about the training experience that covers in lively detail what takes place during a four-day CHI RTI training session.

Reaching Out To New Audiences

CHI co-founders Mark Mudge and Carla Schroer embark on a journey that starts with the place where they met and concludes with top-flight presentations in the UK: