PMG Photographic Processes

Conservation Specialties

Conservation Specialties Analysis and Imaging Preventive Care Education and Professional Development Workplace Practices About Conservation Lexicon

• Photographic Material

Group

• Photographic Materials Group

Section

• Materials

Page Information
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

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". .

"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". .

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 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 Paper

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

Crayon Enlargements, Charcoal Enlargements: Early Hand-colored Portrait Enlargements

References

Copyright 2024. Photographic Materials Group Wiki is a publication of the Photographic Materials Group of the American Institute for Conservation. It is published as a convenience for the members of thePhotographic Materials Group. Publication does not endorse nor recommend any treatments, methods, or techniques described herein. Please follow PMG Wiki guidelines for citing PMG Wiki content, keeping in mind that it is a work in progress and is frequently updated. Cite this page: Photographic Materials Group Wiki. 2024. 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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