[alt-photo] Re: Copy film (Kodak 4125)

[etienne garbaux]

Kevin wrote:

>[Ilford Ortho Plus] handles the production of our step wedges very 
>well. We haven't found a film as consistent since Kodak Commerical 
>and Copy films were discontinued. There are several good films that 
>are useable but are as dependable. Granted, the Dmax varies from 
>emulsion to emulsion batch. There have been a couple of years when 
>getting a 4.0 optical density was next to impossible.

Yes, I can see how IOP would be good for that, except for the 
struggle to get sufficient D-Max.  Have you tried Adox Ortho CT?  I 
have gotten excellent results in copy applications (though it is 
still a single-emulsion film and thus lacks the flexibility of Kodak 4125).

I have been meaning to try Adox Display Film, but have not gotten 
around to it.  They say it is a paper emulsion coated on film 
base.  Unfortunately, Adox does not seem to provide the extensive 
sensitometric/densitometric data that Kodak and Ilford have 
historically done, so one has to do it all oneself (as a careful 
practitioner always should -- but it is nice to know what the 
manufacturer thinks its materials should do).  If I'm missing some 
available Adox technical data, I'd love to hear where to find it.

I don't know how you expose/produce the step wedges (I'm sure many 
list members would be fascinated to know, if you don't consider it 
proprietary) -- if it is by a timed exposure (rather than xenon 
flash), I'd think that the most consistent results would be obtained 
with slower films and longer exposures.

Best regards,

etienne