peterburkmisher: I wish I knew! I've been wondering about all this myself, and where even this knowledge lies these days. Materials scientists? Chemists? It sees a question too specialized for the former, and not specialized enough for the latter? Please anyone who knows...?

More generally:

Josef Maria Eder's "History of Photography" [1] is a semi-technical survey of 19th and early 20th century processes. Part of what it makes it wonderful is the narratives of so many chemist/photographers trying to get their discoveries supported by scientific societies and/or the market, with vastly varying success. As Eder was actually there doing the work[2], he has much to recount.

Much more recent, Richard Benson's "The Printed Picture"[3] takes on how images have made their way to paper. Benson probably knew as much about this as anyone still alive.[4] If in Philadelphia, it's possible still to catch an exhibition of his work.[5]

[1] https://archive.org/details/EderHistoryPhotography

[2] https://www.metmuseum.org/art/collection/search/296322 is a beautiful example

[3] http://www.worldcat.org/oclc/495363201

[4] https://printedpicture.artgallery.yale.edu/color-photography

[5] https://philamuseum.org/calendar/exhibition/richard-benson-w...