[alt-photo] Copy film (Kodak 4125)

[etienne garbaux]

Back in the thread about making contrast masks, I wrote:

>The basic idea is that you sandwich the negative 
>emulsion-to-emulsion with an unexposed sheet of film.  Copy film is 
>best, if anyone still makes it -- it is [was] typically a long-scale 
>blue-sensitive film similar in speed to enlarging paper -- 
>essentially, a #0 or #1 paper emulsion on a clear base, and very 
>slow in film terms.  Some was even contact-printing speed (even slower).

One more point about copy film, which made it hugely useful, is that 
it was coated with two emulsions, one quite low contrast and the 
other medium to somewhat high contrast.  This is similar to 
variable-contrast papers, except that the two emulsions were 
different in speed rather than chromatic sensitivity -- the more you 
exposed it, the more contrasty the result for a given development 
condition.  When used to make a copy negative, this had the welcome 
effect of allowing you to adjust the shadow contrast with the 
exposure from the original negative to the interpositive, and the 
highlight contrast with the exposure from the interpositive to the 
final negative (controlling overall density in both cases with 
developer type and development time).

For these reasons, I sorely miss Kodak Professional Copy Film 4125, 
which was discontinued nearly 10 years ago.  I stocked up, but was 
out of it in a few years.  Of course, today one just diddles the 
Levels or Curves controls in Photoshop.

Best regards,

etienne