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John H. Henderson
2-Feb-2001, 10:54
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 watc h a B&W image appear in the developer tray, try color printing with room tempera ture RA-4. It's a blast to see that first color iamge some out! I have to spil l 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 colo r 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 (firs t time buyer gets half price). I had my temp as dead-on as I could, and followe d 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 loade d 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 negative s. 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 Po rtra 160.

The negatives seemed to print OK. The prints didn't seem lacking in contrast, a nd I don't think I made drastic changes to the filter pack after printing some 3 5mm negs.

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

I don't want to experiment a lot with C-41 due to its horse-choking cost, but wa nted 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 kn ew 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 te sts.)

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

Pete Andrews
2-Feb-2001, 12:45
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?

John H. Henderson
2-Feb-2001, 14:08
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 Hicks
2-Feb-2001, 14:25
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 prac tice. Also your commercial lab may have found that customers prefer snappier pri nts.

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 yo u 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 develo per 1:1 and using a longer time. I know it _can_ work but how well with your par ticular 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 H. Henderson
5-Feb-2001, 10:50
Oh...I am using Kodak Supra III. It's what I get at my local photo store.

Bill C
6-Feb-2001, 01:10
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!