c41 uneven development?

[Zaitz]

My own attempts at developing c41 weren't going very well so I decided to send the last batch out again. Am I expecting too much or is there some other issue here? Looks like some form of uneven development to me. I applied a very heavy curves adjustment layer to make the marks more visible. But I do feel it can be subtly spotted in blue skies. The marks also show up more the more I edit the photo. I can even see the marks on the straight conversion with no editing.




On Portra 400 scanned in with an Epson 4990 and converted from raw positive with colorperfect.

I am guessing I am expecting too much. But on another photo with just some smooth blue sky I could see a hint of the same marks and I felt I needed to cover it up with a gradient overlay masked in. I am not editing to the point of the second image but, to me, once the marks are visible, on any level, it's no good.

[Daniel Stone]

looks like there is insufficient agitation. probably during the bleach step.

agitation w/ c-41 is IMPERATIVE, seeing that the development time is very short compared to most b/w or the standard E-6 process.

I'd look at using a different lab, a place that gets LOTS of use. Labs don't stay in business if they continually screw up peoples orders.
Edgar Praus ( http://www.4photolab.com/ ) does great C-41, and he stays very busy with mail-order clientele.

best of luck

-Dan

[Zaitz]

Yeah that is probably where I'll go next. Thanks for the info.

[Ari]

If you plan on trying it at home again, use two water pre-soaks.

I had very bad unevenness in my initial C-41 attempts, until it was suggested to me to use two pre-soak water baths, instead of one.

The difference was immediately obvious and the unevenness disappeared.

[Dave Langendonk]

If you plan on trying it at home again, use two water pre-soaks...

Can you elaborate? how long for each? How are you processing? What size film? I'm having a tough time with 8x10 in Jobo 3005 expert tanks. The developing time at 100 degrees is short and very prone to uneven developing. I don't have this problem with 4x5, only 8x10. I believe it takes too long for the solution to get to the far end of each tube in the 3005. As a result there may be a rotation or two before the negative gets fully immersed in developer. Since development is so rapid at 100 degrees, you can see these rotation marks especially in sky areas. I'm doing one water pre soak now. Not much different than with no pre soak.

[Ari]

Can you elaborate? how long for each? How are you processing? What size film? I'm having a tough time with 8x10 in Jobo 3005 expert tanks. The developing time at 100 degrees is short and very prone to uneven developing. I don't have this problem with 4x5, only 8x10. I believe it takes too long for the solution to get to the far end of each tube in the 3005. As a result there may be a rotation or two before the negative gets fully immersed in developer. Since development is so rapid at 100 degrees, you can see these rotation marks especially in sky areas. I'm doing one water pre soak now. Not much different than with no pre soak.

Dave, the pre-soak procedure is exactly as Dan describes.
I originally got the advice from him

[LF_rookie_to_be]

I'm having a tough time with 8x10 in Jobo 3005 expert tanks. The developing time at 100 degrees is short and very prone to uneven developing. I don't have this problem with 4x5, only 8x10. I believe it takes too long for the solution to get to the far end of each tube in the 3005. As a result there may be a rotation or two before the negative gets fully immersed in developer. Since development is so rapid at 100 degrees, you can see these rotation marks especially in sky areas. I'm doing one water pre soak now. Not much different than with no pre soak.

Dave, last night I did my third run of 8x10 (Efke 50) in a Jobo drum. It's a 3004 drum, so it has inner compartments of a slightly larger diameter and requires more solution than 3005. Used 700ml of 1+25 R09 One Shot for three sheets, preceded by two short presoaks and stopped in a very weak dilution of common white vinegar. Did it all hand-rolled, but the lid I have is a home-modified with a 750-ml cup on the underneath, so the liquid reaches film only when the drum is turned to the horizontal position and rotated - exactly as in a Jobo processor. Absolutely no streaks of any kind. Could it be the developer you're using?

[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.

[Daniel Stone]

DIY c-41 is extremely simple, and the cost savings can really add up if you shoot a good bit. You also get free pushes + pulls

Like Ari, I use (2) separate pre-soak baths BEFORE development.

[Zaitz]

I thought it was simple but my last batch looked quite poor as you can see from my previous thread. Though, these were lab processed and aren't 100% perfect either. Really unfortunate to shoot 4x5 (expensive c41 at that) and not see the quality you desire, for whatever reason. Will probably just send to Praus with my next batch.