I have always used the pot ferr / fix bleach with RA4 paper, always fixing before and then giving a good rinse before the blix. Again mix just before using as it starts deteriorating 15 minutes after the mixing. The strength of these component can easily be one half those used for film, as the color paper responds much more quickly. - David LygaOne nice thing about separate bleach and fix for C41 is the better keeping properties. You can stretch the bleach quite far by regenerating it, making the most of the expensive ferric sodium EDTA.
Can this be done with RA4?
Only commercial blix I can find here comes in pre-mixed 10L ektacolor bottles. Well above my yearly printing frequency and I'm assuming it doesn't keep for super long after open.
Scratch mixing would be nice but if I have to keep dumping out precious ferric ammonium EDTA the math doesn't work that well.
PS: Could C41 bleach and fix work for RA4? I know that C41 uses a different EDTA salt but PE did once post an old experimental formula for RA4 blix with ferric sodium EDTA. I can live with experimental for paper.
Not sure if I agree. Many instances of backwards compatibility are just a matter of luck. Note that PE never said it doesn't work. He pointed out that it's unverified/uncertain, especially in terms of long term stability.That is how it usually goes with marketplace products.
Why fix before Blix?always fixing before and then giving a good rinse before the blix.
I cannot refute you but my method is easy and not cumbersome. That are differences within this broad panoply of chemical answers. That what the forum is all about. My way works and is both easy and inexpensive.Ah I see, that makes sense. Yes, developer + ferricyanide will generate dichroic fog. Thorough rinsing and/or a sulfite bath should do the trick. If the fix-Blix procedure works for you, that's fine of course. It makes sense, even if there are several (not necessarily better) ways to skin that particular cat.
There should not be a postprocess dye degradation due to the Bleach, assuming the Bleach compound being washed off.As C41 film isn't rated for Ferricyanide bleach, there's no guarantee that dyes that are exposed to Ferricyanide will remain intact in the long run though immediately after bleaching the film they may look fine.
Also, please note that color products are designed to give the best color with a defined sequence of pH and a final correct or optimum pH.
PE
Maybe it would be easier 'to dare' trying it if you did as I do: Do tests with only one or two frames and about 20ml of solution.Yes, I've read your posts about dilute c41 and to be honest, I've never dared try it. So I certainly cannot argue with your experience. Am I skeptical? Certainly. But I have no facts to back up my skepsis! If it works for you consistently and reliably and has so for years, I couldn't (and wouldn't!) even begin to argue that you're "wrong". The same with your apprach to RA4. It's nothing like mine, but if it works, it works.
Some of the film stabilizers, added during coating, are phenolic or HQ like with some of the properties of Vitamin E. That means that they absorb the oxygen that can diffuse into your film or paper during ageing and the oxygen can either oxidize the dyes or the stabilizer. Some of these can be sensitive to Ferricyanide. Thus my caution above.
This is my first explanation of my reluctance to support use of Ferricyanide. The products simply were not tested under those conditions when I was running the tests, so I have no idea. All I can do is put up a warning sign. We won't know for sure for half a lifetime from now probably.
PE
PE's comments are not without great merit. All I can say is that I have used this for years with many different types of C41 films. I have NEVER had trouble. Theory is sometimes trumped by every day experiments. I do have a feeling that this (continued) use of potassium ferricyanide was anticipated by the present manufacturers of C41 film and safety was 'built into' these films. That is how it usually goes with marketplace products. - David Lyga
How do you regenerate the bleach, using own chemicals or a commercial replenisher?One nice thing about separate bleach and fix for C41 is the better keeping properties. You can stretch the bleach quite far by regenerating it, making the most of the expensive ferric sodium EDTA.
What could be the primary reason that my old color photographs from 1980's are fading while the ones from 1990's on fujifilm paper are just as good as back then? The 1980's prints went soft/yellow, and to my surprise the 1990's are super crisp. Just opened up an old photo album. I'm assuming the fading mechanism in RA-4 paper is similar to that of the film.
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