This is a good site for basics on identifying nitrate films as well as a nice mix of film info for collectors and preservationists.
https://www.scart.be/?q=en/content/shor ... ollections" target="_blank
From the site...
Evolutions like the rapid obsolescence of technologies and formats, the leap from the analogue to the digital realm and the ever-growing production of audio-visual materials create great challenges to all institutions that collect, manage and safeguard audio-visual collections. The SCART website gives access to an ever-expanding pool of knowledge on the preservation of audio-visual heritage that is being created by PACKED vzw and its partner organisations. It aims to help memory institutions and others with the task of preservation.
Talk about the work of collecting, restoring and preserving our film heritage here.