The Atlas of Analytical Signatures of
Photographic Processes, The Getty
http://www.getty.edu/conservation/publications_resources/pdf_publications/atlas.html
The Eye, Martin Jürgens
http://the-eye.nl
Graphics Atlas, Image Permanence Institute
http://www.graphicsatlas.org/
Photographic Processes, Gawain Weaver Art Conservation
http://gawainweaver.com/processID
Photographic Process Identification Webinars, Image Permanence Institute
https://www.imagepermanenceinstitute.org/process-id-webinars
Preservation Self-Assessment Program, University of Illinois
https://psap.library.illinois.edu/collection-id-guide#photo_image