c41 uneven development?

[Dave Langendonk]

Dave, last night I did my third run of 8x10 (Efke 50) in a Jobo drum...

I'm referring to C-41 processing, not B&W. I have no problems with B&W. They come out perfect. Development time for C-41 at 100 degrees is only 3 minutes 15 seconds. Very short for rotary processing and for 8x10 it's very prone to uneven development. Thanks for the comment though.

[koh303]

Don't bother looking at the scanner. The artifacts are due to poor agitation in development and/or aerial oxidation between baths. If you're spending the coin to shoot 810, you owe it to yourself to check out LTI/lightside.

Looking at the scanner cannot hurt, especially since it will take all of 20 seconds to rule it out. Until that is ruled out all the MANY pots on this thread are theoretical ASSumptions.

[frotog]

Wrong. I know what bad rotary artifacts look like just as I know what scanner banning looks like. This is experiential, not theoretical. The OP's problem is uneven development. Stick to slinging processors.

[Daniel Stone]

Wrong. I know what bad rotary artifacts look like just as I know what scanner banning looks like. This is experiential, not theoretical. The OP's problem is uneven development. Stick to slinging processors.

While I agree with you on the uneven development issue. However, depending on the scanner used and its age(potentially), that could play a part in the equation as well.

Case in point:
A local photo center where I do the majority of my darkroom-related work at the moment has 2 Imacon flextight scanners, an 848 and a 646. Unfortunately they do not get serviced as frequently as I would like, so they occasionally have banding issues. I've mentioned this to them before, but it seems to fall on deaf ears most of the time. The line of "we have experienced budget cuts, so we'll attend to it when we have the funds" can only go on for so long. But they have a few Epson flatbeds which occasionally band as well.
sorry to ramble.
But there CAN be issues(at least in my experience) with banding, and it not looking like a hard line. Occasionally the banding can look like a light leak, aka it "fades" away from the point of origin in terms of density. Similar to what the OP has shown in his shots(towards the left edge on the 1st shot in particular).

-Dan

[LF_rookie_to_be]

My Scanmate drum scanner from 1995 also has banding issues at times, and they're 100% related to memory and SCSI. A simple procedure of reinstalling SCSI card drivers, restarting and doing several full-drum previews in ColorQuartet (OS X 10.4 system) solves the problem. The lines vary in appearance - hard, one-pixel wide, soft, entire/partial drum circumference, "fading", etc.
Dave, I'm yet to develop 8x10" colour negatives, but I wouldn't do it with less than 750ml for 4 sheets in my lid/3004 setup. This week I'll be developing ten 4x5" C41 sheets with 400ml in a 3010 drum. It's my standard volume for 4x5" C41 (and E6) and so far, no streaking issues. I agitate and roll the drum as much as possible and very fast.

[koh303]

As a matter of experience, imacon machines (and many epson units) often get dust particles to rest on the light bulbs, resulting in lines across the direction of the scan. As the negative is curved, or the scanning head moves the lines vary in width, sharpness and density. This is just one of many other causes of "banding" or "unevenness" in scanning negatives. If the issue on these negatives is not visible to the naked eye there is no way to tell where the issue is. Since checking the scanner takes only a few seconds, why would anyone be against ruling it out? The worst that can happen is to find that it is after all a good scanner, and bad negative development...?

[Dave Langendonk]

...Dave, I'm yet to develop 8x10" colour negatives, but I wouldn't do it with less than 750ml for 4 sheets in my lid/3004 setup. This week I'll be developing ten 4x5" C41 sheets with 400ml in a 3010 drum. It's my standard volume for 4x5" C41 (and E6) and so far, no streaking issues. I agitate and roll the drum as much as possible and very fast.

Sorry for the VERY late reply. I haven't been on the forum lately. I use 1000ml when I do 8x10 in the 3005. I don't believe that is the problem. As I mentioned, I only see this issue with 8x10 C-41. 8x10 B&W are fine since the development time is much longer. 4x5 C-41 also come out fine in a 3010 drum. I have more testing to do but at $12/sheet, testing gets expensive quickly. I process on a Jobo 2300 automated processor and will do some rotation speed changes to see what that does. I use 50 rpm currently as recommended by Jobo for the Expert drums.

BTW, 400ml seems a bit light for 10 4x5's. It may be enough volume to cover the sheets but wonder if it's enough developer to develop them fully. Kodak recommends 3 8x10 equivalents per liter or 10 per gallon for Flexicolor. YMMV.

I wonder if the OP solved the unevenness problem? Zaitz?