Quote Originally Posted by Gerald C Koch View Post
I am surprised that no one has mentioned that the notch codes can be "read" in total darkness.
This is not a practical thread way off topic…
But in a similar vein photogs who had six or more identical blad backs would nail file an additional notch in each so they could tell which back a film with eg a light leak or bad frame space came from... don't everyone do that with dark slides/film holders?