RA-4 Processing Problems

Hi everyone. I've finally made the plunge and taken a stab at printing color myself. Results thusfar have been very promising, but I'm having some problems with streaks on the prints. I'm using one of those drum processors. It has what appears to be two sets of grooves for 8x10s, although it appears there is also another groove inside of the 8 inch wide set, maybe for 5x7s or something. Now I've been getting these purplish or tan streaks on the paper prints, whether I print two prints at once or one. I'm using 2 fluid oz. of developer and blix in each batch. The streaks might be caused by the groove for 5x7s. So should I be using more developer and blix for each bath? Or is this something that is characteristic of not using a stop bath? I want to use a stop bath, but I don't have any glacial acetic acid to dilute to 1% for proper stopping. Can I use Indicator stop bath concentrate instead? What dilution should I use?

Regards.
~Karl Borowski

You don't say which tanks you're using so it's impossible to say if 2 oz is enough or not enough. My tanks need at least 60 ml which is more then 2 US oz.


I just use white vinegar for the stop bath.

Sorry, I didn't have the info on me when I first posted. It is a Unicolor Unidrum, which I use with a rotary motor for agitation. Diameter is approximately 6 1/2 in. Length of the drum is 11 1/2 in. As for the metric equivalent of a fluid ounce, I believe you are wrong. I believe it is between 29, and 30. Using my SmarterChild cheat on AIM, it says that it is exactly 29.574 mL. Maybe you were thinking of Imperial fluid ounces?

Regards.
~Karl Borowski

For reference my smallest 8x10 drums which take a single 8x10 print requires 75ml of chemistry. The next size up which sounds similar to yours and does 2 8x10's requires 100ml of chemistry although I need to increase this for Ilfochrome to 150ml. I suspect you may be a little short on the chemical quantity required for the drum but someone who knows the specific drum can probably help further.

Regards,
Roger.

Somewhere, I've read that Kodak requires .75 ml of chemistry per square inch of paper (sorry for the mixed systems). That works out to 61 ml for an 8 X 10; 101 ml for an 11 x 14, and about 300 ml for a 16 x 20.
Whatever the source, I've used those amounts for that last 10+ years, with no problem as far as coverage goes in my JOBO tanks, rotated horizontally.

A couple of caveats:

First, it is essential that the tank is *dry* when loading the paper. I alternate 1500 series tanks, wiping them out after the final wash with a large high-tech wad of paper towels - Bounty works well. If they are loaded wet, you WILL get streaks/ spotting/ assorted misery.

Second, If you rotate the tank horizontally be sure that it is level.

Third, you are loading the paper with the emulsion side toward the center of the tank...

Shortstop: Yes "Indicating" stop bath is perfectly acceptable. You can also make a perfectly acceptable 1% acetic acid stop bath by diluting white vinegar ( I use "Ozark Distilled White Vinegar - reduced with water to 5% acidity") additionally 1:4 with water.
I've learned that shortstop IS essential in RA-4 processing, between color developing and bleach fix. That is the only place I ever use it.

Oh, yes ... Kodak Indicating Stop Bath should be diluted -- 16 ml of concentrate to 1 Liter of water.

FilmIs4Ever said:

Now I've been getting these purplish or tan streaks on the paper prints, whether I print two prints at once or one. I'm using 2 fluid oz. of developer and blix in each batch.

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Sounds exactly like the streaks I had when drum processing Kodak paper without using stop bath.
Indicator stop baths are ok as long as they are acetic acid. Citric acid like Ilfostop may couse brown stains.
Please post your results after you have tried it with a stop bath.

RA4 processing problems

ekjt said:

Sounds exactly like the streaks I had when drum processing Kodak paper without using stop bath.
Indicator stop baths are ok as long as they are acetic acid. Citric acid like Ilfostop may couse brown stains.
Please post your results after you have tried it with a stop bath.

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I have been colour RA4 processing for about 6 months and in my ignorance just assumed that Ilfostop indicator stopbath was just as good for RA4 as for B&W and to date have never seen any brown streaks.

Using a Jobo 1500 series tank I tried to do 2 x 5x7s at a time but gave up as every so often I would get problems of incomplete developer coverage as the two sheets stuck to each other due to rotation. While there is enough room for two sheets of 5x7 in the drum there is no facility for separators.

On only two occasions have I experienced small green/blue streaks but this has been twice in about 300 prints. I cannot give an explanation but it may have been not drying the drum completelybut at this frequency have just accepted it.

For what it is worth I use Tetenal and replenish as if I was using a Nova slot processor by pouring dev, stopbath and blix back into their containers each time which are in the Jobo waterbath. At the required interval I then discard 100mls and replace. Actually only developer seems to get used and I am not sure whether I need only replace the chemical used say 100mls or should still discard a 100mls and then replace by say 200mls to make up the 1 litre container. This is very economical and provided the chemicals are covered by gas such as Tetenal Protectan which excludes air then I have found that storage of working strength chemical for at least 2 months is OK.

Pentaxuser

pentaxuser said:

I have been colour RA4 processing for about 6 months and in my ignorance just assumed that Ilfostop indicator stopbath was just as good for RA4 as for B&W and to date have never seen any brown streaks.

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This was discussed in another photo forum some time ago and my personal experience confirmed it. One well known professional photochemist who frequents there explained that the phenomenon is due to citric acids capability to form citrate-iron chelates which may interfere with bleachfix action.
Those discussions are easy to find with search engines.