Defective Tetenal RA-4 blix
I just encountered an interesting problem.
About a year ago, I tried RA-4 reversal processing. As I had problems with getting decent highlights, I now tried it again but got even worse highlights and overall gray image. I worked a few days with it and tried different kind of workarounds (adding halide solvent to first developer, etc.) as I believed in Tetenal RA-4 blix I had just made. But finally I found out that the blix was guilty to my problems. Having only a little bleaching and fixing power, it produced gray results that got even more gray in daylight. I just tried re-bleaching and fixing this time's first print. You can see the difference between re-bleach-fixed and original part:
Seen this, I bleached and fixed again my reversal RA-4 tests from a year ago. But the blix wasn't the issue then; they were fine. So that time the poor highlights were due to too high developer dilution and/or too short dev time. Maybe I'll write about my reversal RA-4 experiments later, but now I'm troubled with the problem of defective blix.
The funny thing starts here. I also tried bleaching and fixing again normal RA-4 prints I made two weeks ago - but they were fine. The only thing I did after that was that I made a new blix - but I used exactly the same concentrate.
The blix I'm using now has quite large amount of solid matter in it. I have to rub it away when final washing the print... The previous Tetenal RA-4 kit didn't have this much crud in it.
Have I done something wrong? How is it possible that the new blix made from the same concentrate as before is not working at all?
Another problem I've found with this Tetenal blix - and maybe with the previous batch too, I'm not sure - is that the paper whites gets very yellowish and smudged if the blixing is carried on too long - 45 seconds seems to be maximum in order to get good results. Is this normal?
Should I report this problem to Tetenal and/or try different blixes?
As a workaround, I'm now using ferricyanide bleach and E6 (ammonium thiosulfate based) fixer.
- Antti Alhonen.
Last edited by hrst; 02-22-2009 at 07:38 PM. Click to view previous post history.
Look at the clear portion and the red portion of the blix before mixing. I would guess that the clear portion is cloudy and/or has scale on the sides of the bottle or a precipitate in the bottom. The red porion is probably clear.
If so, this indicates that your hypo is bad.
Mix up 100 - 200 ml of standard ammonium thiosulfate solution in 1 liter of water and add 10 g/l Sodium Sulfite and 10 g/l Disodium EDTA. Adjust the pH to 6.5 and add it to 1 liter of the red part and dilute to 4 liters total volume.
This should be fine.
Your photo is overexposed by several stops and needs more red filtration.
The blix has a poor shelf life when concentrated. Does the tetenal kit come as a blix concentrate or with two seperate bleach and fix concentrates? The blix decays and gets a strong sulfur smell with flakes/crud of god knows what and stops working well. You should not have crud/have any problem over blixing with good blix. Your blix is dead. Complain. Buy the Kodak stuff.
As soon as the sink is installed in the darkroom, I'm going to try some RR4 processing. I noticed the print referenced above is blue - what is the cause of this?
Thiis is an RA-4 reversal process.
There is no comparison to the neg-pos process.
This is cross processing.
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Yeah, I forgot to mention that Tetenal kit has only one concentrate for blix. It is just diluted to working solution. It indeed looks dead... What can I do to avoid this problem in the future? That is to say, I have one Tetenal RA-4 2,5 liter print kit waiting to be opened... Can the aeration of blix concentrate be the problem? I have not diluted the whole kit at a time, but to make one third at a time. Or is the problem with this Tetenal's "Mono-concentrate" -- should I buy some brand having two concentrates for blix?
Is it okay to use potassium ferricyanide bleach (40 g/l potassium ferricyanide, 25 g/l sodium bromide) and KODAK E6 fixer with RA-4? (Of course with proper washes before and in-between.) It seems to work very well.
Regarding the reversal RA-4 process, it seems very interesting, and although I wasted much time with this blix problem (trying to fix it buy changing exposure, filtering and developer :-)), I have quite a good results now. I've examined both Kodak and Fuji papers and different concentrations of sodium thiosulfate added to first developer. Maybe I'll start a new thread after I have some more concrete information to share about reversal RA-4. It's almost ten times cheaper than Ilfochrome! http://sorsa-tv.ath.cx/~antalh/siwachrome/scan007.jpg - this is not so blue as the first one ;-).
Last edited by hrst; 02-22-2009 at 11:34 PM. Click to view previous post history.
Originally Posted by hrst
You really cannot make a single part blix that is stable.
If your blix came as a liquid in one bottle, it is probably dead by the time you get it. You are mixing an oxidant and a reductant (Ferric EDTA + Hypo) and it self destructs.
It will take about 1 - 4 months, but how long is it sitting on the shelf?
Okay, I was wondering the same. Tetenal, way to go! They advertise this as a good feature, making it more easy to mix. It would indeed be very painful to mix two liquids ;-D.....
The developer is the same, only one concentrate, whereas C-41 have three concentrates, for example. But the Tetenal ra-4 dev works very fine and seems to have long shelf life, even with one concentrate.
Next I'll buy KODAK :-).
Last edited by hrst; 02-23-2009 at 11:29 AM. Click to view previous post history.
Originally Posted by Photo Engineer
Tetenal states that this RA-4 kit has got an `optimum protection against oxidation´ (whatever that means).
Further they state that a partially emptied bottle of Blix mono-concentrate would keep 6 months.
However, they ask to use protective gas on this bottle.
This does not make much sense to me. That gas will protect the hypo from being oxidized by air, but is not that bleach the greater threat for the hypo?