Thanks for the link to this. Great photos.
Do you know how the numbers show up on the negs? I assume that the film holders were marked to determine which negative came from which holder. This would be very useful if a holder was defective.
Good record keeping can key a negative to a holder. For cataloging, the number can be inked in the edge of the negative. I file five wide or narrow notches in the flap on film holders. Using binary coding, this gives me 32 numbers for only five notches.
Jim, Thanks. Les