I'm a member of a small team of volunteers who have transcribed and translated several 17th century documents (in abbreviated Latin). The documents obviously are long out of copyright (if copyright ever applied to them) but are the property of an individual who has given their permission for the work to take place.
We obviously own the copyright in the translation, and I understand we would have no copyright in a letter-for-letter transcription, as that's pure format-shifting -- like copying a film from a VHS tape to a DVD. And of course, we have moral rights, so we can (I believe) insist on being credited for both transcription and translation.
However, the heavily abbreviated nature of the original means that we needed to put a lot of work into expanding the transcription to be complete (a 'semi-diplomatic' transcription) before we could create an accurate translation. Perhaps 10-15% of the transcription is text we have inserted (and marked as such). Another transcriber might have made different choices for conjugating and declining the Latin, and even identifying the abbreviated words. Or they might have made the same choice...
Does this affect the copyright status of the transcription? (I suspect I know, but want confirmation).
(There's no commercial value in the work, but a number of the parties involved in recruiting us to do the work are awfully confused on the subject...)
I've looked at Manuscript transcription - but am still unclear.