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

[Kevin Morris]

Okay, first off, sorry for the empty reply. I’m using a laptop for the first 
time and am still getting used to it. I keep touching the mouse pad while I 
type and depending on where the mouse happens to be I'll send the email 
before I've typed.

Anyway, I have tried the Adox Copy. It is useable for small jobs. However, 
it isn't consistent enough from batch to batch. The problem we run into with 
most of the film we have tested is that once we test a small amount (usually 
100 sheets or so) and decide to give it a wider testing the next batch of 
film that comes in isn't anywhere near what the the last batch was like. 
There have been coating problems, different base color and density curves 
that are nowhere close to previous curves.

I won't go into a lot of how we make the 21 step, among others, but I can 
say what we use. We use approximately 10,000 sheets of IOP a year along with 
several 100 sheets of NDT X-Ray film of various sizes. All the film is 
exposed with incandescent light. Depending on the job 1 to 3 different 
wattage bulbs are used with or without neutral density. We have two dip and 
dunk processors used in production. One has a batch size of 12 8x10's (with 
8 gallon tanks) and the other can run 40 sheets (30 gallon tanks).  Ilford 
Phenisol is the developer we use. It may not work for others but is is a 
good, all-round developer for all the film we run.



-----Original Message----- 
From: etienne garbaux
Sent: Wednesday, October 27, 2010 5:10 PM
To: The alternative photographic processes mailing list
Subject: [alt-photo] Re: Copy film (Kodak 4125)

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




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