Last weekend, I ventured into color processing (C-41) and printing (RA-4) using my Jobo CPE-2.

If it's been a long time since that first thrill you got the first time you watch a B&W image appear in the developer tray, try color printing with room temperature RA-4. It's a blast to see that first color iamge some out! I have to spill the beans - it's not the witchcraft that some people lead you to believe. And I did not need to spend $300 on a used dichroic head. I used a $30 set of color filters in the filter tray. You spend so much time in the chemicals, exposing, focussing, etc., the time spent changing filters is not significant.

Anyway, my questions focus on 4x5 C-41 process. I used Tetenal's C-41 kit (first time buyer gets half price). I had my temp as dead-on as I could, and followed the included instructions - 3:15 in the developer, etc. I used the chemicals one shot in the 2500 series drum with one 4x5 reel, no more than 4 sheets loaded at a time.

So I get out color negatives. Yay! But the unexposed background (the "mask" I guess) is darker than with my plethora of professionally-processed 35mm negatives. They also don't have the contrast of the 35mm negatives, but they might just appear that way because the mask is so dark. The film was Kodak Pro 100 and Portra 160.

The negatives seemed to print OK. The prints didn't seem lacking in contrast, and I don't think I made drastic changes to the filter pack after printing some 35mm negs.

So, do the 4x5 emulsions just have a darker mask than 35mm emulsions? I don't have any 4x5 negatives to compare. Am I not bleach/fixing long enough? (I am following the recommended times).

I don't want to experiment a lot with C-41 due to its horse-choking cost, but wanted to know that I could do it if I had to - particularly for 4x5 since no one locally processes it. (and mailing 1 or 2 sheets at a time is expensive if I knew where to send it.)

Can I put a negative BACK into bleach/fix after stabilizing and drying to try to reduce the mask more? (The negs I have are of nothing important - they were tests.)

BTW - Bleach/fix resembles blood and you'll have it all over the place. Just adds to the image that my friends have of me being some mad scientist working in my lab in my castle at night while lightning strikes all around!

-- John H. Henderson (jhende03@harris.com), February 02, 2001

Answers

Last time I processed 5x4 in C-41, I used Vericolor 3, and the mask was almost exactly the same as other formats processed commercially. It's possible that the bleaching hasn't been done fully, leaving a bit of silver in the emulsion.
Do the prints seem more grainy than they should?

-- Pete Andrews (p.l.andrews@bham.ac.uk), February 02, 2001.

I hadn't noticed any grain in the prints, but I'll look more closely when I get home.

It couldn't hurt to drop one of the negs back into the blood for a few minutes and see it it makes any difference. I'm a big proponent of experimentation.

-- John H. Henderson (jhende03@harris.com), February 02, 2001.

Some labs, especially consumer minilabs, develop the film a little longer to try to compensate for any underexposure in consumer-exposed film as a standard practice. Also your commercial lab may have found that customers prefer snappier prints.

You can freely adjust development time to give the contrast you want up to the point of causing crossover.

As for the blix, it goes to completion so while you can always under-bleach you can't over-bleach with any remotely reasonable blix time. You can re-bleach.

One thing you may want to experiment with to lower cost is diluting the developer 1:1 and using a longer time. I know it _can_ work but how well with your particular film, developer and processing equipment I have no idea.

I don't find it at all cost-effective to run C-41, but otoh there's a good lab that runs C-41 six blocks away.

-- John Hicks (jbh@magicnet.net), February 02, 2001.

Oh...I am using Kodak Supra III. It's what I get at my local photo store.

-- John H. Henderson (jhende03@harris.com), February 05, 2001.

John, I concur with the suggestions to rebleach/fix. This is a standard first step for labs in troubleshooting high base density problems with the C-41 process (unless they have an IR scope which they would use first.).

Of course, it's possible that the bleach/fix is bad in some way, but if it's working at all, another 3-4 minutes should reduce the base density further (only if there is a retained silver problem). Also, rather than rebleach/fix an entire neg, submerge one only halfway (do it by hand). That way, if there is a change it's visually obvious.

Congrats on your first run! Also, just in case you don't aready know this, let me warn you that both of these developers (C-41 and RA) are considered to be skin "sensitizers". That is, after some period of exposure to them, you MIGHT develop an allergy. If so, it can be so bad you won't want to have anything to do with color developer anymore. So read the MSDS (if you got them) and the handling instructions carefully. They will likely recommend at least wearing gloves and wash thoroughly with a low pH soap (like pHisoderm?) after handling. Have fun!

-- Bill C (bcarriel@cpicorp.com), February 06, 2001.