[alt-photo] Re: Copy film (Kodak 4125)
photographeur at nerdshack.com
Wed Oct 27 21:10:13 GMT 2010
>[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.
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