8x10 C-41 rotary processing. Where did these marks come from?

Sjixxxy · Jan 7, 2012

A few weeks ago I was given some expired 8x10 films from a fellow APUGger. Mix of Fuji & Kodak 160. Thought I'd see if it would work developing them two at a time in half a 2850 print drum in my Jobo with the digibase chems. First eight sheets I developed were absolutely perfect. I had four more to develop today so I mixed up some new chemistry and went at it. Developed two Kodak sheets. Then immediately developed two Fuji sheets.

After drying I tossed the Kodak sheets on the scanner. Something wasn't right. Bunch of ugliness near the film holder marks, and right edge.

Only thing I did differently was cut the chemicals to 250ml instead of 300 I had been using. I figured if there was some degree on unperfect levelness, that would account for the right side marks, but what about near the top & bottom of the sheet?

Then I put the Fuji sheets on the scanner that I developed afterwards expecting some of the same. Nothing. They look perfect.

Any ideas on what might have happened with the Kodak sheets? FWIW, it even looks like the blank area where the film holder edges are don't have even density.

Sirius Glass · Jan 7, 2012

From Instruction Manual For The Jobo CPA-2 & CPP-2 Processors, 1997

page 23

Caution: Do not use print drums to process sheet film. All modern films have an antihalation layer coated on the back (base) side of the sheet. This layer is removed during processing by chemicals flowing over the base side of the film. The rails of the print drums inhibit the flow of chemicals to the base side. If the backing of the film is not cleared during processing, dark spots or lines will be evident on the film. Print paper does not have an antihalation coating and therefore is not affected by this issue. Some duplicating or display transparency materials processed with 'print' chemicals also have an antihalation backing, so check the manufacturer's specifications to see it it does. If the transparency material does have an antihalation backing, it must be processed in a film or Expert Drum.

Consider obtaining a 3004 Expert Drum - 4 sheets

This is not what you wanted to here, but I believe this answers your quandary.

Steve

Sjixxxy · Jan 7, 2012

Coming from a position of almost complete ignorance on the subject - does that explanation jive with what appears to be the added density following film holder marks? If it were a rib in the tank, I'd expect them to run all the way across. Instead of backing off in the upper right corner like it seems to be doing, right?

As for this not happening on the other ten sheets - dumb luck?

Sirius Glass · Jan 7, 2012

I do not know.

Which processor are you using?

Do you have a Jobo Manual? If not, are you set up to take an FTP of 60 MB? The CPP2 Service Manual is 9.5 MB

Go to the APUG Classified Page and click on Amazon.com. Find a copy of The Rotary Processor Manual, John Tinsley, R. Morgan Publishing

Sjixxxy · Jan 7, 2012

CPE-2. SO I don't think I could even use an Expert drum.

I'll do a boring scene photo tomorrow and run it back at 300ml since that was working just peachy. See what happens. 120ml is recommended on the drum, maybe somewhere between 250 and 300 is the sweet spot where the chemistry over-deluges enough to win?

Sirius Glass · Jan 7, 2012

I do not have information on the CPE-2. Start a new thread and ask if anyone has the CPE-2 manual that they can scan and make a pdf file for you or you can search amazon.com or eBay.

JLP · Jan 7, 2012

I don't think it has anything to do with processing, i do think there is a chance that you have a filmholder that is leaking or you could accidentally have pulled the slide a fraction before or after you exposed the film.

Sirius Glass · Jan 7, 2012

A light leak in a film holder would make a dark image on a negative and a light image on a positive [slide or C-41 print]. That is not in evidence in post 1.

wildbill · Jan 7, 2012

was the kodak film open or sealed when you got it?

polyglot · Jan 7, 2012

Does the negative have less density in these areas or is it visible only in the scan?

I have to say they look like flare from the scanner, i.e. lots of light coming through the film base at the edges and darkening the image parts nearby. The fact that the shape of the dark bits is identical in both orientations would seem to exclude the issue being one of fluid dynamics in rotary development.

I get this effect when scanning 120 in my Nikon 8000 unless I'm careful to mask the negs with card and reduce spillover light coming through the inter-frame gaps. If I don't mask carefully, I get darkened frame-ends that look identical to the horribleness you show here.

Edit: the effect is more noticeable with thinner negs. Are these two bad ones thinner? Or perhaps you did something slightly different in the scanning.

Sjixxxy · Jan 8, 2012

wildbill said:
was the kodak film open or sealed when you got it?

A bag with five sheets were jammed in a box of Fuji. Fuji bag was unopened that was sharing the box was unopened.

wildbill · Jan 8, 2012

there you go. continue with your tests but moisture may be the culprit. I've seen it before on the edges of sheet film that's been lying around. Since it sits so flat together, the moisture only gets to the edges and sometimes the film sticks together at the edges too.

darkroom_rookie · Apr 19, 2012

Sirius Glass said:
Consider obtaining a 3004 Expert Drum - 4 sheets

What is the minimum quantity required for E-6 if the drum is to be used rolled by hand? I did 9 4x5" C-41 sheets in 3010 drum with a modified lid (epoxied cup) hand-rolled and it worked great, no marks whatsoever (every negative was contact-printed). The lid/cup takes 460ml. Will that do for 4 8x10" E-6 sheets in 3004 drum?

8x10 C-41 rotary processing. Where did these marks come from?

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