hckrnws

The page is pretty sparse there, with a bunch of links to the actual meat which is interesting.

from the introduction:

The main purpose of the Atlas is to help a conservator and curator formulate analytical questions related to a particular photograph and, at the same time, assist a scientist unfamiliar with analysis of photographs when interpreting the analytical data. The Atlas also contains a number of interpretation guides that provide help with photographs of similar analytical signatures, with identification of overlaps of spectral peaks, and with warnings of potential misidentification or misinterpretation of analytical results.

at https://www.getty.edu/conservation/publications_resources/pd...

But looking at just the front page you might be underwhelmed if it was not in your particular area of interest.