Mark Osterman's Posts

Mark Osterman is the Process Historian in the Kay R. Whitmore Conservation Center at George Eastman House. Best known for his depth of knowledge in the area of collodion photography, Osterman is also internationally recognized for his research and teaching of photographic processes from Niepce heliographs to gelatin emulsions. Osterman's curriculum, once reserved for the international conservation community, is now available to the public through a series of hands-on workshops at Eastman House and other venues in the U.S. and abroad.

A Piece of History Reborn

Posted by on Jun 29 2015 | Behind The Scenes, Photography, Technology

In 1995, before I was hired to teach in the conservation department, my wife and I originally came to Eastman House to teach workshops. Back then, we brought a car load of equipment from home—cameras, studio stands, and other specialized photographic equipment—every time we held a workshop. Now, twenty years later, my full-time job at Eastman House is once again teaching public workshops in historic photographic processes . . . and, I’m still bringing equipment from home.

The technology collection at the museum holds more than eight thousand cameras. But as Todd Gustavson, curator of the technology collection, tells me, once an object is officially accessioned into the collection, it becomes an artifact available for study—not for actual use. It’s understandable. Damage to equipment is expected when a piece is handled by many or exposed to corrosive chemicals, particularly the wet collodion process used to make tintypes and ambrotypes.

In the past few years, I’ve been scrounging for original equipment for the workshop program so that eventually we’ll be fully equipped without the need for me to loan pieces to the museum. We run our workshop program without a budget for equipment, and the supplies are funded by an additional fee paid by the participants. A few months ago, I decided it was time to get an 8×10” studio camera for the program, and I used social media to get it.

I made an appeal to our friends. We host the Eastman House Historic Processes Education group page on Facebook with more than 2,800 subscribed friends. In less than a day I had two people willing to donate the type of camera we needed. One was in New Jersey and the other was in Ohio. The Ohio camera, owned by Jeannette Palsa, also had the original studio stand—both in need of restoration, but solid. Jeannette had taken an ambrotype workshop from us years ago and uses the process in her fine art photography.

On a Friday in April, my assistant, Nick Brandreth and I drove the four hours to the Akron area to retrieve the camera and stand. When we arrived, Jeannette’s friend Bob Herbst was also there with a second camera donation. Jeannette was kind enough to send us off with box lunches and we arrived back in Rochester with two cameras, a studio stand, and a speeding ticket from an Ohio speed trap.

That weekend, I disassembled the studio stand, made the necessary repairs, refinished the wood and iron castings, and had it ready for use by Tuesday of the next week. The better camera of the two, an 8×10″ Century 10A Studio Camera donated by Bob was chosen for use since the bellows were still in usable condition and it only need some minor repairs. I made a lens board for this camera and attached a large brass portrait lens from my personal collection so that we could use it right away. Eventually we’ll be looking for a replacement lens and new bellows to be made, but the camera was put to use immediately in a tintype workshop less than a week after bringing it back to the museum. It’s a great piece of history reborn.

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Brandreth (left) and Osterman (right) with the century 10A Studio Camera donated by Bob Herbst and original studio camera stand donated by Jeannette Palsa.

Brandreth (left) and Osterman (right) with the century 10A Studio Camera donated by Bob Herbst and original studio camera stand donated by Jeannette Palsa.

The workshop program is always looking for donations of equipment, from laboratory glass, to vintage photographic apparatus. Contact Mark Osterman at if you think you can help.



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The Revival of Gelatin Emulsion Making

Posted by on Mar 25 2013 | Photography

Coating film

We’ve been preparing for this workshop for two months now. My research assistants Chris Holmquist and Nick Brandreth and I just finished our first public workshop in making, coating, shooting and processing gelatin emulsions. Ron Mowrey, ex Kodak emulsion engineer, was also there to answer any theoretical questions.

Haven, Nick, Joe and Dave (1)

I designed the formula back in 2004 as a basic 1880 type emulsion used for gelatin dry plates negatives. It’s very much like what George Eastman’s chemists would have made.

We had seven attendees during the four day workshop and we’ll have six more come to the second session. The first day included an illustrated lecture on the history and chemistry and then we demonstrated how to make an emulsion in daylight to give everyone a chance to photograph each step. After that we divided into two groups and they each made batches of silver bromide gelatin emulsion.

Joe Gelbro Workshop (1)

On the second day we coated 4×5” test plates, exposed them in the George Eastman House gardens and processed them in the darkrooms. The next morning we evaluated the negatives, looked at amazing original prints in the photograph collection and rare emulsion making equipment in the technology collection. We ended the day by coating more plates.

Nick additionI (1)

The third day we spent most of the time shooting and processing plates. In the late afternoon we coated plates for shooting the following morning. On the final day we shot and processed in the morning and at lunch evaluated the plates and Nick scanned them for reference. We went out and shot a group portrait …on our emulsion. Chris ended the workshop with a demonstration of coating the emulsion on paper and film.

Emulsion Group I 2013

This wasn’t the first time gelatin emulsion making has been offered to the public, but given the scope of what the group learned, what they saw and what they produced, it was a landmark workshop. We hope that the interest in emulsion making and shooting will grow like it did after we taught the first public workshops in collodion here at the museum back in the 90s.


More information about our photo process workshops here

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Why are they called Tintypes? There isn’t any tin!

Posted by on Mar 14 2012 | History, Other, Photography

Well, I guess I forgot how easy it was to make a tintype; no cutting or cleaning glass and no pictures peeling off the plate. This was all about pouring the collodion and making a unique image in the time it takes to make a cup of coffee.

We started on Monday at George Eastman House with an illustrated presentation on the chemistry and history of the wet collodion negative and positive processes. Then we went down to the technology archive where curator Todd Gustavson presented a display of original tintype cameras, silver baths and other rare equipment.

Curator of Technology Todd Gustavson (far left) with group. 


After lunch we went to Scully & Osterman Studio where they met my wife, France. I gave a demonstration of making a tintype that included tinting and burnishing the picture. The group then practiced the techniques of pouring collodion onto tintype plates and applying the developer.

Pouring Collodion on the Plate.


On Tuesday we all met at Scully & Osterman and after a morning recap on theory the group I gave a demonstration of mixing iron developer and France demonstrated mixing iodized collodion. The group spent the rest of the morning shooting 4 ¼” x 5 ½” plates. After a lunch break they continued to make 5” x 7” tintypes into the afternoon. The students varnished their own plates themselves before shooting the next image. At the end of the day I discussed the basics of identifying antique lens types, explained how a wet plate conversion back works and demonstrated a simple traveling darkroom made from cardboard.

Wednesday we shot all morning. After a great lunch we continued shooting into the afternoon. For the last day in the studio we shot 6½” x 8½” whole plates. Some of the students actually used an original four lens tintype camera that exposes four images simultaneously on the same plate. Late in the afternoon we went back to the Museum and viewed some really beautiful examples of vintage Melainotypes, ferrotypes and tintypes.



Oh, the term tintype evolved to be the name for all collodion images made on thin sheets of metal; none of which were made of tin. Cheap things in the nineteenth century were often made of tinned iron that was coated with a shiny black finish applied to the surface to prevent rusting. Since Melainotypes and ferrotypes were the cheapest images you could buy and made on black finished sheets of iron…the term tintype seemed to fit nicely. By the way, we didn’t use tin either, we made our tintypes on aluminum.

Our next collodion workshops are Ambrotype Making here in Rochester in May and the Ambrotype and Tintype Workshop at Fox Talbot Museum, Lacock England in July.

Check out more images on our Facebook album for this Workshop.


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A Photographic Revolution in Rochester!

Posted by on Feb 14 2012 | History, Other, Photography

Sure, the times are changing and technology moves foreword. Yes, it’s sad that films days are numbered, but quit your whining. There’s another revolution in photography and it’s coming from Rochester, the “image city.”  I’m referring to the counter culture of historic photographic processes and they’re hot. Photographers all over the world are making their own plates and papers— and they’re doing it here at Eastman House.


Azo print made with the gelatin emulsion process being taught in April

Tintype being fixed


Coating paper in the gelatin emulsion darkroom 

 Scully & Osterman Skylight Studio, where we’ll shoot tintypes in March


The revival in the daguerreotype process started at George Eastman House back in the 1970s. Hey, we also jump-started the current craze in collodion photography by teaching the very first wet plate workshops in the mid-1990s. In the last two years we introduced dry collodion plates, collodion chloride printing-out paper and even did workshops in the earliest processes of Niepce, Daguerre and Talbot… the heliograph, physautotype and photogenic drawing! In private tutorials here at the museum we’ve taught albumen on glass and even orotones!

In March we have a great three day Tintype Workshop where we’ll make plates under the skylight over at Scully & Osterman Studio and see amazing original images and even collodion era cameras and equipment from the archives at the museum.

Gelatin silver emulsions are soon going to be the next historic photographic process revival and now is the time to gather information before the culture is gone. This April ex-Kodak emulsion engineer Ron Mowrey and I will teach our third gelatin emulsion workshop!

This is the real stuff for all you people who have been so upset about the demise of emulsion. We’ll be making a simple printing paper emulsion, but it’s the first step to the more advanced film emulsions; so one step at a time. If we get enough interest we’ll give a film and plate emulsion workshop next year, but the prerequisite would be the basic workshop. So, the way to keep film alive…is to make it your self!

Read more about all our 2012 Photography Workshops, or contact me directly at to arrange a private tutorial, custom group workshop or if you need some advice with a process that’s giving you trouble.



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John Deere Tractor Green Carbon Printing

Posted by on Apr 25 2011 | Behind The Scenes, Other, Photography

I had a small group last week for the carbon photography workshop, which made it easier for me and unusually spacious in the darkroom for the participants. Though no matter how few people you have making carbon prints though there never seems to be enough hot water, so calls of “more hot water” were regularly heard in the darkroom for three days.

We made the first batch of carbon tissues using casting frames, coating rods and our fingers so that everyone had the experience of trying different ways to make the tissues. After everyone made their initial exposure tests and first prints we made two new color batches of pigmented gelatin and prepped other support material; watercolor paper and glass.

David Developing Carbon


Drying Tissues


‘John Deere tractor’ Green Orotone


My demo in action

One of the colors that came from this freedom of extra time was a sort of John Deere tractor green. We also made a lovely cool blue tissue. One of the participants wanted to make a carbon transparency on glass and at the time thought he had chosen the blue tissue. He was really surprised when we turned on the white lights during the development and saw that his beautifully made transfer was actually green. When the plate was dry I held a sheet of bronze coated paper behind the image so the group could see how it would look as an orotone. The green wasn’t so bad.


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