Captions and subtitles need "bibles" just like theatre pieces or movie productions. Like their literal iterations, these collections of information are guides for all the relevant players on how to present content so that it's clear, correct, and, most of all, consistent.
When I was a captioner, some shows had 'em and some didn't. Worst was when we had to consult fan wikis for character name spellings, backstory, etc. VODS, shows, and movies need bibles templated and used, if they're going to commit to full accessibility for all users.*
Depending on where the captioner or subtitler is, there are differences in how they would normally write as a layman and how they would do their work. A Canadian captioning a show from and about the States would defer to American dictionary spellings and definitions and standard writing style guides, plus the client's house style guide. But an American subtitling an import series from Scandinavia would be wise to not only adhere to the client's wishes and that country's standard guides but also recommend other applications based on show content and branding, audience composition and an eye to future distribution potential.
Show bibles vary from artform to artform. It may well develop to have set and costume notes and samples, helpful visual ephemera, guidelines on authorized style guides, character details, notes on directorial changes and edits (updated), and all of this should be backed up—at least twice. Hard copies might also be wise should the internetalypse happen midproduction.
Here's an example of what Netflix's much (self-)touted subtitling policies did not address or succeed at (or this wouldn't have happened).
Peaky Blinders, Season 4, Episode 5 (accessed December 2017). In one scene, Cockney Jewish character Alfie Solomons is saying Good boy but the caption says Goodbye. Perhaps the non-native captioner (or one without British background or dialectic familiarity) should not be the titler for dialogue if they can't understand the accent, let alone understand that Goodbye wouldn't even make sense in the context if that were the audio. It causes errors and (although apparently not here) extra costs in QC corrections.
Image: cropped screenshot accessed Netflix, Peaky Blinders, December 31, 2017.
If a show bible is not extant or available, a good editor will do some research and preferably some subsequent consultation. The latter should be done by the most qualified expert in their professional network: moms with English degrees don't count. Having established some form of NDA, the editor should present their problem and its context, their research, and a suggested edit to the consultant. Confirmation or correction should lead to a fix, and either way the edit should be flagged with a justified query or note to the managing editor. Time is tight on titling projects, but there's no excuse for guessing. I have a time limit on how long I'll do my own research before turning to an expert; if I can't get the ME a recommended edit, I'll pass on my recommendations for next steps.
This example also points out the pitfalls of having blinders on about vendors. Perhaps your regular multilingual translator in Europe is multitalented, but this show would have required a titler who had ties to or experience with people in London and Birmingham, for instance.
Another problem with this scene was when, in the same episode,
Alfie Solomons was captioned as speaking Italian when in fact he was speaking Yiddish...
...but the captioner didn't have enough linguistic background to tell the difference between gutteral and romance language phonemes. (Note that although different, captions and subtitles are sometimes needed in the same product. Read more here.) The titler should have consulted someone (or perhaps shouldn't have been contracted in the first place). I have a whole discrete presentation I can give about foreign language subtitling inconsistencies within Netflix captions; see the Engagements tab to book similar lessons and discussions.
So a bible, shared with the captioner, would have been available to tell them that Alfie Solomons is a Jew from the East End, living in Birmingham, with the common interruptor of the area's "yeah" and that he has no known connections to the Italian language. These are two instances where Netflix would have been saved embarrassment from YGWYPF vendors. If they aren't embarrassed, simply in terms of access to content for the deaf they should be.
Bibles can be simple, and they don't have to be pretty. But they do need to be complete, proactive, shared and USED.
*Read here about who should be using captions and/or subtitles (and sometimes both); it's not just a "deaf problem."