> I wonder if they thought of these photos as a record for posterity, or just an incidental work-product Typically both. That's why the plates were carefully c

> I wonder if they thought of these photos as a record for posterity, or just an incidental work-product Typically both. That's why the plates were carefully cataloged. It was not uncommon for plates to be exposed/developed and not actually be looked at by a researcher for months or years. It's not researchers were lazy but if they were doing a survey and have 100 plates it took time to get through them. A plate needs its provenance cataloged so when handed to a research assistant they've got the metadata needed to properly catalog the plate's contents. Even in the plate days researchers would do meta-surveys comparing plates they may have done with archived plates made years or decades prior. Lots of comets, asteroids, and other transient phenomena have been discovered because a researcher has been able to look at decades worth of exposures to some patch of sky. In the 90s I remember reading about a lot of universities/observatories digitizing their plates (then on CD-ROM) so they were more readily available to contemporary researchers.