Reducing Contrast in Optical Printing

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VulGerrity
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Joined: Tue Mar 19, 2013 10:36 pm
Real name: Michael Gerrity

Reducing Contrast in Optical Printing

Post by VulGerrity » Sat Jun 29, 2013 6:27 pm

I've been doing a lot of optical printing lately on a J.K. Optical Printer and an Oxberry printer. However, I've noticed that my prints are coming back extremely contrasty. I'm not currently printing with any contrast filters, just white light and ND filters to knock down the exposure. I've been printing my film onto 16mm EXR 7244 Intermediate print stock and I'm processing it as black and white for 5min in Dektol with a 1:1 dilution. I know Dektol tends to be a more contrasty developer, but it's cheaper, and I haven't had any contrast problems when developing my camera original negatives.

Is there anything I can do when optical printing to reduce the contrast and get some information back? When I'm printing, the film tends to come back looking almost like I printed it on 7363 High-Con film. My teacher mentioned putting diffusion in front of the white light may reduce contrast, is this true? I also just read something that said over-exposure and pull processing can help reduce contrast as well.

Thanks for you help, anything you can give me would be greatly appreciated.

richard p. t.
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Re: Reducing Contrast in Optical Printing

Post by richard p. t. » Wed Jul 03, 2013 2:45 am

Hello vulgerity,
well, basically you have to reduce your gamma (contrast). You can reduce the gamma by a) using a different film stock (!), b) changing to a lower contrast developer or c) increasing the exposure and reducing the development time. It should be possible to get very good results from the existing JK or Oxberry light source without tampering with that. IT is the case that optically printing does have a tendency to increase contrast, but by the sounds of it, not nearly to the extent you are experiencing.
One of the problems you are having is that you are shooting on intermediate stock rather than a negative stock. Intermediate stock is designed to have a higher gamma than negative stock. Would be better to use an internegative stock, rather than an intermediate stock. You should also be using a negative developer rather than a paper developer like Dektol. Paper developers produce a much higher gamma than negative developers.
So really, you are using the wrong film and the wrong developer. You would need to switch BOTH of these to get 'normal' results. Switching to a neg developer (probably easier for you than changing your film stock) would help a great deal. It still would be more contrasty than 'normal'. Pull processing would further inprove the situation. But I don't think pull processing the same film with the same developer will get you where you want to go
good luck
where is the oxberry by the way? You are lucky to have access to one of those.
cheers,
richard
I run Nano Lab - Australia's super8 ektachrome processing service
- visit nanolab.com.au
richard@nanolab.com.au

woods01
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Re: Reducing Contrast in Optical Printing

Post by woods01 » Sat Jul 06, 2013 6:42 am

I like to use D-76 to process B&W negatives. If you can get your hands on some old Plus-X, that can be an option to create an internegative from. I've used 7363, 7302 and 7222 to optically print to from positives. Basically whatever is handy and cheap! I havn't done it myself (yet!) but I imagine Tri-X 7266 processed as a negative might give good results to print to, I've always been happy with the results when I've processed that camera stock as a negative.

I'd also wager that since you're developing a colour film in B&W chemistry that it is also creating contrast since not all the dye layers are getting developed.

aj
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Re: Reducing Contrast in Optical Printing

Post by aj » Mon Jul 08, 2013 1:24 pm

Try pre-flashing the film. Either per frame or just the whole roll.
Difficult though is to find the right amount...
Kind regards,

André

VulGerrity
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Real name: Michael Gerrity

Re: Reducing Contrast in Optical Printing

Post by VulGerrity » Tue Jul 16, 2013 5:09 pm

Thanks for the help guys! I'll do some experimenting.

The Oxberry is at The School of the Art Institute of Chicago.

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