Arquivo de etiquetas: Processos Fotográficos

Conferência e workshop na Casa-Estúdio Carlos Relvas 15-17 Out. 2008

(foto daqui)

Especial destaque para a conferência e workshop que se realizará na Casa-Estúdio Carlos Relvas entre 15 e 17 de Outubro de 2008 e que trará Mark Osterman e France Scully Osterman a Portugal para este evento.

Mark Osterman and France Scully Osterman, Rochester, New York, will give a lecture, demonstration and workshop on the Wet-Plate Collodion Process at Golega Studio,
Oct 15-17, 2008.

They will begin with a discussion of collodion history, process, identification and deterioration.
It will be held October 15 at 9 am. Following the lecture, the Ostermans will make an ambrotype group portrait and show examples of variants of the process.

The workshop will begin in the afternoon of October 15 and continue until October 17. In the workshop, students will make self-portraits with a 19th century portrait camera and lens. Participants will be guided through the process step-by-step, from cutting and cleaning glass, to varnishing the final image.

Variants of the process, including Opalotypes, Lantern Slides, and Negatives will be demonstrated. Included will be instructions on mixing chemicals and troubleshooting, plus a manual, “The Wet-Plate Process, A Working Guide.” No equipment is necessary for this class. Workshop attendees are advised to wear dark-colored work clothes, as they may become stained with silver nitrate during this workshop.

About the instructors:

The Ostermans are respected historians and considered modern masters of wet-plate collodion photography. The recent artistic revival of the process is a direct result of their work through exhibiting their imagery, teaching workshops and extensive research and writings on the subject. They are represented by Howard Greenberg Gallery in New York City and Tilt Gallery in Phoenix, AZ.

Mark Osterman currently serves as Photographic Process Historian for the Advanced Residency Program for Photograph Conservation at George Eastman House, International Museum of Photography and Film in Rochester, NY. He recently edited the 19th c. section of the New Focal Encyclopedia of Photography (fourth edition).

France Scully Osterman is guest scholar at George Eastman House, and teaches private tutorials and workshops in the couple’s 19th century skylight studio in Rochester, New York, US.

The couple began publishing a collodion manual in 1995, and published The Collodion Journal from 1995 to 2002. Their work has been highlighted in numerous solo exhibits throughout the US and in publications, including Paris Photo, recent issues of Spiegel, Geo, View Camera, and Zoom magazines, and on-line interview at

Their work is also featured in several alternative and historic process books, Le Vocabulaire Technique de la Photographie by Anne Cartier-Bresson (2008), The Book of Alternative Photographic Processes, 2000, by Christopher James, 2008 edition of Photographic Possibilities, by Robert Hirsch, Coming Into Focus, 2001, by John Barnier, and Photography’s Antiquarian Avant-Guard, 2002, by Lyle Rexer.

The Wet-Plate Collodion Process
What is Collodion?

Invented in 1849, collodion was made by treating pure cotton wadding with nitric acid…then dissolving the “nitrated cotton” in a solution of ether and alcohol. The clear fluid could be poured onto nearly anything and when the ether and alcohol evaporated a thin, clear plastic film was left behind. The word collodion comes from the Greek word meaning to stick because the film has great adhesion. It was initially used to keep cloth bandages in place.

In 1850 it was suggested that collodion might be an effective binder for photographic chemicals.
Frederick Scott Archer (England) published the first working formula for the wet-collodion process in the 1851 issue of The Chemist.
Archer’s process included putting potassium iodide in the collodion and pouring this onto glass. Before the alcohol and ether evaporated from the collodion the plate was taken into a darkroom (under red light) and placed in a solution of silver nitrate. This created silver iodide in the collodion binder making the plate sensitive to light.
The plate was exposed in a camera and brought back to the darkroom to develop a visible image by pouring onto the plate pyrogallic and acetic acid. The developed plate was washed with water and then fixed in sodium thiosulfate (aka hypo) to remove the unexposed silver iodide. The plate was then given a final water wash. When completely dry, a protective coating of varnish was poured onto the fragile image.

– The Improved Process

By the end of the 1850s, photographers added bromide to the iodide in the collodion and the developer of choice was ferrous sulfate (aka iron sulfate) mixed with acetic acid. Another fixing agent was also available. Potassium cyanide was a very effective fixer, though deadly.
Most people using the wet-plate collodion process today use iodide/bromide collodion/ ferrous sulfate developer/ and either hypo or cyanide fixing.

– Positive / Negative Collodion Plates

Because the image silver of a collodion plate has such a small particle size it will appear as a much lighter color than silver gelatin image particles of the same density. Because of this it is possible to make a negative for printing (as illuminated from behind) or a direct positive image when a plate is backed with something dark and illuminated from above.
The difference between the negative and positive is usually density determined by exposure and development, though the actual technique/mechanics are the same.
Positive collodion images became known as “ambrotypes.”
Positive mages made on black sheets of iron were called “melainotypes,” “ferrotypes” or “tintypes.”

The Use of Collodion Photography

Collodion was used for making photographic negatives for portraits and landscapes from 1851until the mid-1880s.
Collodion was used to make ambrotypes from the mid 1850s to the mid-1860s
Collodion was used to make ferrotypes (aka tintypes) until the late 1880s
Collodion was used to make half-tone screened negatives for the printing industry until the 1970s
Since 1851 there has always been some form of photography being done using the collodion process

186 Rockingham Street
Rochester, NY 14620
Centro de Estudos Em Fotografia da Golegã
Curso Superior de Fotografia
Instituto Politécnico de Tomar

Casa-Estúdio Carlos Relvas
Câmara Municipal da Golegã

For registration information, please contact:
Centro de Estudos em Fotografia da Golegã – CEFGA
Curso Superior de Fotografia
Instituto Politécnico de Tomar
Estrada da Serra, Quinta do Contador, 2300 Tomar
Tel. 351 249 328 130
Fax. 351 249 328 135