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  #1  
Old 15th December 2019, 08:28 PM
John King John King is offline
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Default What is this

I thought I had seen it all with 30 years of RA4 printing. However I have had problems these last few nights printing onto Kodak RA4 cut from a bulk roll. It isn't an old roll, only a couple of months old (Since I bought it) with a date of manufacture of May this year and until the last few prints it was perfectly OK. This problem came on suddenly.

What I am getting is an overall yellow cast which I cannot eliminate. I can change the yellow filtration, but that makes little or no difference. Even the margins are yellow. So I think this eliminates the actual filtration. The RA4 kit I am using is the Tetenal 5 litre kit, rather than the Kodak Ektacolor I have used for many years.

I seem to be able to eliminate some of the cast by prolonged washing but not completely eliminate it but even with Tetenal before I have not had to do this. The cast is also appearing in the margins which fades to a pale magnolia shade, but only when they are washed for around 10 15 mins.

I use a DUKA safelight but that has not given me a problem before. If there was an over exposure to the sodium light, then I would think the colour cast would be blue-ish rather than yellow.

The chemicals are relatively new and used in a NOVA deep tank. The temperatures are spot on, (checked with 2 digital thermometers which are less than .5 of a degree apart).

Is it possible that I may have not diluted the bleach/fixer enough. Instead of 4 of blix to 1 of water I may have only diluted it to 3 to 1, so when I bleach/fix the print, the result is chemical staining . I cannot remember what I did when I mixed it three or four weeks ago. However it isn't cloudy and there is non of that noxious pong when blix 'goes off'. The developer, stop and bleach are all replenished at the end of the session.

To be honest I am scratching around for answers.

(I wish I had stuck with Kodak - I never had a problem with that)

Last edited by John King; 15th December 2019 at 08:36 PM.
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Old 15th December 2019, 09:40 PM
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GoodOldNorm GoodOldNorm is offline
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The only time I have had an overall yellow cast was because my paper was old. Not sure why you would get a yellow cast if your paper is not that old. I did forget to take my yellow filter off a lens after shooting B&W film, that gave my colour film a yellow cast but it was nothing to do with my chemicals or paper :-)I also once got a yellow cast when my Nova processor leaked between sections, the developer got contaminated.
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Last edited by GoodOldNorm; 15th December 2019 at 09:46 PM.
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Old 15th December 2019, 10:30 PM
Mike O'Pray Mike O'Pray is online now
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John it would appear from what you describe that you simply got to a section of the roll which for reasons unknown has a yellow cast over the whole paper.

If you are certain that nothing else has changed then it points to a roll where a yellowness starts.

Like Norm I had some cut sheets of quite old Kodak show this yellowness in the margins but in my case I didn't detect this cast elsewhere on the print.

If you are satisfied that nothing else has changed then it may be that you need to run a fair chunk of the roll through just to see if the cast then disappears again - hopefully

A real bummer this one - my sympathies

Mike
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Old 15th December 2019, 10:43 PM
EdmundH EdmundH is offline
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John, you say that the chemistry was mixed three or four weeks ago, have you successfully used this batch? - I have previously experienced slight yellow/orange staining from contaminated Blix (ie too much developer carried over from the stop bath). However it did take quite a few prints to reach that state.

In fact I also found that indicator stop bath was causing 'cream' borders and highlights, so I now use cheaper acetic acid for the stop, and replenish it perhaps 25% after each session to keep the Blix in good order. This has given me noticeably cleaner and brighter prints.
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Old 16th December 2019, 12:48 AM
John King John King is offline
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Default Age of Chemistry

Yes I have used it successfully until these last few nights when it all went belly up. As I said I always replenish at the end of each session at a ratio of 10cc per 80 sq ins of dev, stop and blix. The yellow I am reasonably happy that it is not a 'colour cast' per se but almost certainly chemical staining.

I drained off the bleach/fix tonight and made up a new batch and this time the 1st two or three test prints were OK-ish. Even one which was totally un-exposed, taken from the test strip box to the developer still had this stain. I did a 10x12 and there again it was back. Not as bad as before but the borders when compared with the back of the print was markedly and definitely yellow ish.

I like colour printing but this is becoming a bit tiresome.

Like you Edmund, I also use a non indicator stop bath so we are the same there.
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Old 16th December 2019, 04:25 PM
John King John King is offline
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Default I know what has happened.

It seems that with the collapse of Tetenal there was a breakdown in production until they got up and running again. What stock was left was sent out to dealers when they started working again. It looks like I got one of the old 5 litre kits and despite the May date of manufacture on the box there was none produced during that time.

I have decided to empty the tank and clean up all my colour printing gear and leave it until next year (Jan/Feb) when I will have another go, but this time using Kodak as I always have done in the past. I also have a major darkroom rebuild in the design stage so I will not be doing much for a while.

According to the Imaging warehouse, a colour developer that has the 'starter' incorporated in the kits is not as good as one that has to have it added later. This later addition makes the developer far more vigorous and active which will last longer if regularly replenished. The Tetenal one does not have the replenishment rates in the instructions because it is not designed to be replenished. Possibly they think it will be used in a JOBO drum or similar and then thrown out when finished at the end of the session.
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Old 18th December 2019, 02:02 PM
JOReynolds JOReynolds is offline
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Why combine bleach and fix? The RA-4 process was originally designed to pass directly from developer to bleach, without a stop bath. It allow for a modest amount of carryover. I no longer have the figure to hand (it's more than 45 years ago) but the Kodak technicians with whom I was then working pierced a corner and weighed the wet paper with a spring balance as it came out of the developer. Ferric EDTA bleach is a powerful chelating agent and effective reducing agent, stopping development instantly. The advantages of the original configuration are that:
- the number of slots is the same as using a stop bath
- replenishment is more effective and the life of (expensive) bleach can be extended by many times
- silver can easily be recovered from the fix
- the overall cost per print is lower
- the problems described, of combining bleach and fix, are eliminated
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Old 18th December 2019, 08:44 PM
John King John King is offline
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Quote:
Originally Posted by JOReynolds View Post
Why combine bleach and fix? The RA-4 process was originally designed to pass directly from developer to bleach, without a stop bath. It allow for a modest amount of carryover. I no longer have the figure to hand (it's more than 45 years ago) but the Kodak technicians with whom I was then working pierced a corner and weighed the wet paper with a spring balance as it came out of the developer. Ferric EDTA bleach is a powerful chelating agent and effective reducing agent, stopping development instantly. The advantages of the original configuration are that:
- the number of slots is the same as using a stop bath
- replenishment is more effective and the life of (expensive) bleach can be extended by many times
- silver can easily be recovered from the fix
- the overall cost per print is lower
- the problems described, of combining bleach and fix, are eliminated
Only eliminated if you can buy the separate bleach and fix for RA4 process. Both the Kodak and Tetenal processes come as bleach/fix combined. If it were no good then they would be separate I am not sure if the separate bleach and fix from film processing is quite the same. I always have used a stop bath - recommended to me by a colour processing lab 3 decades ago.

It serves the purpose of neutralising the developer before the blix stage. If you didn't do that the replen rates for blix would be far higher than they are now with the stop bath. Likewise if the blix were two separate baths.

I don't think that is my problem however, it is more than just likely that the problem is with a dodgy developer or possibly cross contamination.
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Old 30th December 2019, 10:00 PM
John King John King is offline
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Default Update

Since my last post I left colour printing alone for a while. (Christmas got in the way.) These last couple of nights I had another attempt and the problem with fogged borders and all the other bits and pieces I had the problem with have GONE!

I have not done anything different. My technique is the same. The paper I use is the same, as is the RA4 developer/Stop Bath/Blix. The Duka safelight has not been moved, and the light level is the same. I simply don't have a clue what went wrong.

I have made 5 prints over the two evenings all without colour problems or fogging.

All I can say is - problem gone, thank goodness for that.
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Old 30th December 2019, 10:35 PM
alexmuir alexmuir is offline
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Good news, John!
I’m glad you’ve got it sorted.
Alex


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