Because of 2 different moderators.
joerivera wrote I thought maybe I had mis-categorized the images as needing a release, so I double-checked and re-submitted them. Now they've been declined with no further transparency is offered. I'm completely baffled at the seeming randomness. |
If a release has been asked it is required (in the eyes of the moderator). It's not what you think what is needed but what the moderator thinks what is needed. Resubmitting without property release results in a refusal. At least that part of the operation is transparent.
Now concerning (c): If you scanned from the original book and the book has been published before a certain date (something around 1900), it is clear that there is no (c) on the published data any more. Artwork after that data is protected for 70 years after the death of the original creator (not the book publisher or the book author). So currently all artwork of a creator who died in 1949 or before is in the public domain. As Dave Merchant points out, that may not be the case for derived work.
Now the moderator has no chance to see if the (c) did effectively run out or not. However, my understanding is, that if your work is considerably more than scanning, you could propose that work as derived art and you may claim (c) on that work. But it's complicated and it is a very complex issue. I suppose, however, that the pictures have been fallen into public domain and that uploading them to a site like Adobe Stock could be considered as a misappropriation of (c) where (c) is no more available. If you want to make the illustrations available to the public, I suggest you upload them at one of the sites offering free pictures.
As there is no mainstreamed appeal process, either you take your chance and continue submitting, hopping that the next moderator does not refuse your pictures or you stop submitting to Adobe stock...