> Layering up the film will work by the way - film base and fog just
> contribute to the overall density and so become irrelevant here - if the
> total density of one layer is 0.15 then the total density of 2 would be
> twice this. As I posted earlier this is really too small a step to work
> with by this method.
But if you're going to have 20 or 21 layers of film, surely it would
interfere with contact. It's very handy to put one of these little
21-steps next to the negative when making a print. In my experience,
even one piece of masking tape on the negative can spoil contact.
I would assume also (judging by my experience with the 19th-century method
of adding up pieces of translucent paper) that numbers written on by hand
would get so strongly diffused through all those layers that the basic
information of contact, sharpness and emulsion behavior conveyed by how
those numbers *print* would be lost.
Judy