tldr: check out
David Seubert, of UCSB, said that the key metadata (beyond what is on
the label) to help people navigate 78s are: date, place, genre. So we
have been trying to get dates (much more to go on genre and place).
It has been a combo of volunteers (thank you!) and then automating the
sources and techniques they used as much as possible.
We get the data from 78discography.com, discogs, 45worlds, dahr, and
most recently we keyed the data in from:
The American 45 and 78 RPM record dating guide, 1940-1959, and
The Almost Complete 78 RPM Record Dating Guide (II)
(let me know if you want the data and we can discuss)
With it we have now gotten 80% coverage, which is the highest yet.
To find what we still need, I made a spreadsheet, sorted by the number
of records we don't have a date for yet:
but it also has a sheet with the current collection, but just label,
catno, date (if any) and web address.
If you have leads on how to find the missing dates, or want to help hunt
for them, most welcome. Maybe this can help you date your collections...
anyway, having fun.