I understand (please feel free to correct me if I am wrong) that by the end of the development process, film is pretty insensitive to light as the light sensitive silver halides have all been converted into something else by the developer
My only experience of this was to find a sheet of film floating in developer when I switched the darkroom lights on when I thought (mistakenly) everything was safely in the fixer bath.
“Oh bother” I said – or something like it
I just grabbed it and shoved it straight into the Fixer missing out the Stop completely.
I didn’t bother to note which negative it was, I was too keen on making sure it was fully immersed in the fix.
Now I have printed the batch of Negs, I am reasonably certain of which it is, but not because of any apparent increase in Base Fog but because it is slightly more contrasty compared to the others in that batch.
It surprised me; I thought I would have ruined the Neg but seemingly not.
BTW – I wouldn’t recommend normally collecting Negs out of the Developer under normal light – it does your heart rate no good at all – but it is fascinating to see just how fast the film turns milky and then clears in Fixer – about 30secs or so and it was clear – I thought it would be far longer
Personally, I have never used the BTZS Tubes - but I thought you were recommended to do the Stop & Fixing under a dim Safelight?
Martin