I think the illegible or missing pieces necessarily need to be left blank (I.e. [???] ).
I had an experience recently transcribing some documents from “Women of the Early Republic” in which various Petrarch sonnets and writings of various early Italian poets were written in a notebook as reference quotes. But here’s the thing…the Italian in the notebook contained a number of misspellings. Some items of Renaissance Italian vulgate were updated to more modern Italian, and some were simply spelling or transcription errors that differed from the original. I used as reference the original text to try and decipher the cursive writing, but I followed the Italian as written. Had I corrected the writing to the official version of those texts it would not have been accurate to the document being transcribed.
Regarding postage stamps/postmarks/envelopes, here is the text from the present guideline (link noted in an earlier entry):
"Envelopes
Transcribe all legible text from envelopes, including from postmarks and postage stamps. Postmarks and postage stamps should usually be marked as marginalia."
I’m glad you brought up the LC perfin as I think there’s been a lot of confusion on whether to transcribe it in the sheet music campaigns. I usually include it, but I haven’t gone out of my way to edit it in if everything else in the transcription is correct when reviewing, but not sure if that’s the correct approach.
Yes! I would like to see one of the community managers weigh in on this. @carlyn-btp maybe? I can see where maybe it should be included when the letters are facing the right way, but I’m very doubtful when looking at the page from the back, where the letters are facing backwards. Having said that, I’m pretty much ignoring them as well.
Do transcribe page and catalog numbers and letters. You are welcome to capture property and other ink stamps indicating ownership. It is not necessary to transcribe perfins (perforated letters or numbers) when encountered.
Images
Ignore images. Don’t describe or note them in the transcription box. If a page has only images and no text, click “Nothing to transcribe.” You can use tags to capture information about images, watermarks, postage stamps, or any other non-text features.
And a note about postage stamps - when encountered on an envelope, kindly refer to Transcription: Unusual Text:
Envelopes
Transcribe all legible text from envelopes, including from postmarks and postage stamps. Postmarks and postage stamps should usually be marked as marginalia.