PMG Photographic Processes

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Date initiated: January 2010
Contributors: Amy Brost, Luisa Casella, Tatiana Cole, Kim R. DuBoise, Lisa Duncan, Monique Fischer, Saori Kawasumi Lewis, Amanda Maloney, Alejandra Mendoza, Elsa Thyss, Laura Wahl, Stephanie Watkins


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Photographic Process Identification

Many photographic materials look similar, yet the chemistry behind them varies greatly. "Without detailed knowledge and understanding of the photographic processes used in making a given photograph, it is extremely difficult to determine the environmental conditions needed for the photograph’s long-term preservation, as well as the maximum light levels that should not be exceeded during display or exhibition. A detailed knowledge of the process chemistry, the processing and post-processing treatment, and the potential deterioration pathways is also needed when developing conservation and preservation treatments". [1].

"The identification of photographs and photographic processes based solely on visual and microscopic inspection of photographs can be used to answer more than 75% of identification questions successfully". [1].

Process Identification methodologies

Graphics Atlas

The Graphics Atlas from Image Permanence Institute presents a Photographic Process Identification Methodology and Controlled Vocabulary that analyzes the key identifying features of each photographic process. By observing and identifying the characteristics of each photograph, the unique combination of features leads you to a correct identification.

These key identifying features in this methodology are divided into three groups:

1. Object View

  • Primary Support
  • Image: Color/Tone, Quality
  • Formats/Mounting
  • Finishing Techniques
  • Deterioration Characteristics
  • Information Written or Printed on Object


2. Surface View

  • Surface Sheen
  • Surface Texture
  • Deterioration Characteristics


3. Magnification

  • Image Structure
  • Layer Structure
  • Deterioration Characteristics


The Atlas of Analytical Signatures of Photographic Processes

The Atlas of Analytical Signatures of Photographic Processesby Dusan Stulik and Art Kaplan is intended for professionals that may need to identify more unusual photographs and that may have access to analytical techniques to study them. It provides identification information in terms of:

1. Visual Signatures

  • Visual Characteristics
  • Microscopic Characteristics


2. Analytical Signatures

  • XRF
  • FTIR
  • Other Analytical Signatures relevant to each process


CAMEO of the Museum of Fine Arts, Boston, contains information and representative images of various photographic materials, including a short reference list. Gawain Weaver compiled a useful controlled vocabulary of photographic processes that includes a list of synonyms and specific products associated with photographic processes.

Photographic Process Chronologies

Chronology of Flexible Films

Photographic Process Chronology

Photographic Processes List

The list of photographic processes below is modeled after Bertrand Lavédrine's organizational structure, with permission.
The pages linked below aim to offer a baseline knowledge of photographic processes from a Photograph Conservator's perspective, and list links particularly relevant for the preservation and conservation of those materials.

Positives on Metal See also Cased Photographs

Daguerreotype

Heliograph

Tintype

Positives on Glass See also Preservation of Glass in Photographic Materials

Ambrotype: Positive Collodion See also Cased Photographs

Crystoleum

Color Screen Processes

Autochrome

Lantern Slides

Lippmann Process (Interferential Color Process)

Opalines, Opaltypes, Opalotypes

Positives on Plastic

Dye Diffusion Processes

Holograms

Positives on Paper

Albumen

Lightly Albumenized Salt Print

Bromoil, Oil-Pigment

Carbon

Carbro, Ozotype, Anthrakotype, Ozobrome

Chrystotype

Collodion-Chloride Printing-Out Paper (POP)

Crayon Portraits, Solar Enlargements and Painted Photographs see also Treatment of Crayon Portraits

Cyanotype, Blueprint, Pellet Print, Argyrotype

Dye Transfer or Dye Imbibition

Gelatin Printing-Out Paper (POP)

Gum Bi/Dichromate

Photogenic Drawings, Salted Paper Prints, and Calotype Prints

Platinum, Palladium

Silver Gelatin Developing-Out (DOP), Resin Coated (RC), Photostat

Uranium Prints

VanDyke Brown, Kallitype, Brown Print, Sepia Print, Ferro-Gallic, Argentotype, Agyrotype

Mechanically Printed Positives on Paper

Collotype

Letterpress/Half-tone

Photogravure (etching)

Woodburytype See also Carbon

Mechanically Printed Positives on Paper or Plastic

Computer-generated digital-sourced print See also Digital Prints

Negatives on Paper

Albumen Negatives

Salted Paper Negatives

Negatives on Glass See also Preservation of Glass in Photographic Materials

Collodion Negative See also Cased Photographs

Gelatin Dry-plate Negative

Lantern Slides

Negatives on Plastic Film

Black and white negatives on plastic support

Color negatives on plastic support See also Preservation of Traditional Color Photographic Materials

Mechanically Printed Negatives on Paper or Plastic

Computer-generated digital-sourced print See also Digital Prints

Dye Mordanting and Silver Toning Processes

This category is defined in Sylvie Pénichon's book[2], referign to prints or transparencies made with dye mordanting or silver toning processes.

Silver Toning Processes

Polychromide

Triadochrome

Polychrome
Chromatone

Dye Mordanting Processes

Diachrome
Uvatype, Uvachrome, Vitacolor
Curtis Neotone

References

  1. 1.0 1.1 Stulik, Dusan C. and Art Kaplan. 2013. The Atlas of Analytical Signatures of Photographic Processes. Los Angeles: The Getty Conservation Institute.
  2. Pénichon, Sylvie. Twentieth-Century Color Photographs: Identification and Care. Getty Conservation Institute, 2013.


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Cite this page: Photographic Materials Group Wiki. 2026. Photographic Materials Group Wiki. American Institute for Conservation (AIC). Accessed [MONTH DAY YEAR]. https://www.conservation-wiki.com/wiki/Photographic_Materials


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