RA-4 for E-6 film?

I was looking at yet another video (this one from Mat Marrash) on exposing RA-4 paper in camera for reversal, to produce a direct positive (with suitable filtration), and it occurred to me: RA-4 uses CD-3. E-6 also uses CD-3. Both processes develop to a B&W negative first, then fog (with light or chemicals) and develop the remaining halide with color developer before bleaching and fixing away the silver to leave only the dye positive.

Has anyone attempted processing E-6 film with a first developer like Dektol or Rodinal (at suitable dilution, of course, possibly with some thiosulfate or thiocyanate added for highlight clearing), followed by light exposure for reversal and RA-4 color developer? Because I'll have RA-4 chemistry on hand for color printing, going forward, it would make small-volume E-6 much more accessible vs. the cost of E-6 kits (that will surely go off before I can use up their capacity). I know I've read about people running E-6 with Dektol followed by C-41 chemistry -- but because C-41 uses CD-4, the colors will always be at least subtly shifted.

Both E-6 and RA-4 reversal (can) run the color developer to completion, so the only time/temp critical step would be the first developer; my presumption is that I'd select a dilution that, at process temperature, would give FD time similar to canonical E-6 process.

Obviously, this would make no economic sense for someone who doesn't already have color printing chemistry on hand -- RA-4 chemicals are sold in quantities that make them senseless for a few rolls of E-6 a year (though the concentrates might be expected to keep pretty well). However, for someone who already processes B&W and C-41, the only additional chemicals needed to process E-6 this way would be the RA-4 developer (replenisher and starter, perhaps only the replenisher since you're processing to completion), which is fairly reasonable.

I remember reading here on photrio about some people trying it with decent results, I did it with Rodial + c41 on a scrap of film and the results were not too bad.

A friend of mine does it here in Brazil. He still has problems with his first developer, but he’s getting closer every day.

Not sure about long term dye stability, but I guess a good wash and a final rinse with a little formalin should work.

Dye stability ought to be fine, RA-4 uses the same developing agent (CD-3) as E-6 color developer. As noted, C-41 stabilizer (available from Unique, I think, same as Flexicolor chems) or a low concentration formalin ought to work (E-6 films don't have the stabilizers in the emulsion the way post-2000 C-41 does?). One roll of 35mm Ektrachrome, cut into test strips, ought to get one awfully close on the first dev, and all steps after that can be carried to completion or aren't time-critical. If the color developer weren't to be carried to completion, different activity levels might cause problems -- but after first dev, you want to develop all the remaining halide anyway.

RA-4 has less CD-3, and more Bromide. Wouldn't that give you color casts and I remember PE saying something about bromide and iodide concentrations being tuned to emulsions.

@laingsoft I'd expect that to cause trouble in a controlled development like C-41, but in E-6, the color developer is (or can be) carried to completion -- after which, it shouldn't matter how fast it got there. This is why (for instance) Cinestill can offer three different first developers that produce different color balance or overall contrast with the same color dev. The color balance change is just a "color shift" due to adjusting the relative rates or amount of development given the color layers in the first dev; the "increased dynamic range" is balanced development to a lower contrast. Which is to say, almost everything that goes wrong in E-6 is a first developer problem.

Obviously, I wouldn't try this first on rolls of Ektachrome I've already exposed, and on which I care about the images. I'd start with test rolls, likely clips of 1/3 roll of 35mm exposed with a test scene (including a gray chart and/or Shirley, to satisfy the color critics).

I don't have any 35mm E-6 film on hand, unfortunately -- it would be convenient if I did, since I'll be mixing RA-4 chemistry this weekend.

E-6 color developer also contains Citrazinic Acid, which reduces contrast. You will likely get slides with RA-4 CD, but they can have contrast and color balance all over the place. I'd be more willing to try funny stuff with C-41, since most of it is scanned anyway, and color corrections are easy in digital post. With E-6 slides you may feel tempted to project some in future ...

Rudeofus said:

E-6 color developer also contains Citrazinic Acid, which reduces contrast. You will likely get slides with RA-4 CD, but they can have contrast and color balance all over the place. I'd be more willing to try funny stuff with C-41, since most of it is scanned anyway, and color corrections are easy in digital post. With E-6 slides you may feel tempted to project some in future ...

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I've seen the method of controlling contrast in RA-4 process, adding (small amounts of) sulfite to reduce contrast and peroxide to increase it. Since these are adjustments that go to the core of how color developers work, they ought to have the same effect in any use of a color developer -- hence, if I find the color contrast is too high I can add a small amount of sulfite to the color developer. Unlike using an E-6 kit, there's no expectation of keeping and reusing the RA-4 working solution anyway (in fact, it might well be diluted more than it would be for prints in a tray or drum -- this is surely the case with, for instance, Dektol).

And not too much danger I'll be tempted enough to pay for a medium format projector, or subject others to "slide shows" that I had to sit through when I was a kid (never really understood why my uncle felt the need to shoot Kodachrome while a missionary in Honduras, though photographically it was probably a better choice than C-22 Kodacolor for that climate). The E-6 film I have waiting to be processed or (years expired) waiting to be exposed is all 120 (though at least one roll will be on a 620 spool when it comes out of my Reflex II); some is 6x9. I could buy a drivable used car for the price of a 6x9 projector (though I'm sure I could build one out of enlarger parts for a great deal less) -- and good luck finding mounts that size these days.

Donald Qualls said:

I've seen the method of controlling contrast in RA-4 process, adding (small amounts of) sulfite to reduce contrast and peroxide to increase it. Since these are adjustments that go to the core of how color developers work, they ought to have the same effect in any use of a color developer -- hence, if I find the color contrast is too high I can add a small amount of sulfite to the color developer.

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I have never read, why Citrazinic Acid works better than Sodium Sulfite, but Kodak would have used sulfite if sulfite would have done the job. Citrazinic Acid was already used in E-4, so its use was neither new nor novel. One possible reason not to use Sulfite is, that PPD sulfonates are still developers and may - after oxidation - react with dye couplers to form wrong/unstable dyes. PPDOX coupled with Citrazinic Acid would not do this.

Donald Qualls said:

And not too much danger I'll be tempted enough to pay for a medium format projector, or subject others to "slide shows" that I had to sit through when I was a kid (never really understood why my uncle felt the need to shoot Kodachrome while a missionary in Honduras, though photographically it was probably a better choice than C-22 Kodacolor for that climate). The E-6 film I have waiting to be processed or (years expired) waiting to be exposed is all 120 (though at least one roll will be on a 620 spool when it comes out of my Reflex II); some is 6x9. I could buy a drivable used car for the price of a 6x9 projector (though I'm sure I could build one out of enlarger parts for a great deal less) -- and good luck finding mounts that size these days.

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The images projected from a 6x7 capable projector a breath taking. If you go this route, you should try to get as many slide frames as possible. AFAIK these were only produced by Gepe, and they stopped production last year. I just found 30 frames on ebay, but they are rare. For 6x9 I would not even know, where to get projectors and/or slide frames from. 6x6 is more available, both from the projector side and from the slide frame side.

@Rudeofus I don't know that much about the chemistry of color developers, and I just know what I've seen on YouTube and read here about printing RA-4. My understanding is limited to the dyes being composed of developer oxidation products bonded with appropriate dye couplers.

Beyond that, however, in B&W reversal, the second developer is carried to completion; as is the case in RA-4 reversal. Seems to me it's also the case in E-6, which confirms that contrast in reversal is, as frequently emphasized, controlled solely by first developer. I wouldn't expect a contrast controller in RA-4 to prevent full development -- at most, it might mute the colors slightly, but I'll know after I do enough tests to nail down the first developer. After all, the sulfite and peroxide additives are done in RA-4 color dev in order to change the overall contrast of a print -- so the same developer that already has the citrazinic acid still responds to that "more oxidation/less oxidation" control.

Testing by developing to B&W negative would be the simple way to arrive at correct first dev parameters, but a silver filter layer would require partial bleaching to make a negative visible for assessment. Most likely I'll have to do the whole process -- first dev, stop, wash, light fog, color dev, bleach, fix (or blix -- I have Flexicolor bleach and fixer, as well as RA-4 blix), wash, stabilize? -- to get film I can evaluate, then repeat with changes to the amount of halide solvent and time for the first dev, until it works right.

I still don't see much danger of getting into projecting slides of any size. The main reason to shoot chromes in medium or large format is that the end result, when correctly processed, is far easier to scan to an accurate representation than a masked color negative. My main interest is that there's only one choice for color negative film in 4x5 at this time. If I want to shoot anything other than Portra 160 in my Speed Graphic or Graphic View, I have to buy Fuji, and that means chromes. Working out the process on 35mm (1/3 roll at a time) and confirming it on 120 is FAR cheaper than making my mistakes on 4x5 Velvia. Even if it works out to be perfectly successful, processing E-6 in RA-4 chemistry won't replace E-6 kits for the mass market -- it would only make sense if you already print RA-4 and have the chemistry on hand.

But if you do print color, RA-4 (assuming it works) is a much cheaper way to process them than E-6 kits, and shooting chromes and printing from those by RA-4 reversal opens a group of additional film stocks (and their characteristics) that can be printed, and thus images enjoyed by others without the need for a projector, screen, and darkened room.

Donald Qualls said:

@Rudeofus I don't know that much about the chemistry of color developers, and I just know what I've seen on YouTube and read here about printing RA-4. My understanding is limited to the dyes being composed of developer oxidation products bonded with appropriate dye couplers.

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This is mostly correct, but if you mean "develop to completion" in E-6 CD step, it does not mean "until it runs out of dye couplers", but "until it runs out of developable silver ions", and this is the main point of Citrazinic Acid. It is a competitive coupler, i.e. oxidized CD-3 can couple either with a dye coupler, or with Citrazinic Acid. If you add enough Citrazinic Acid (or H Acid, or J Acid), all the developable silver ions will provide oxidized CD-3, which will then react with the Citrazinic Acid and produce no dye. If you add sulfite instead, the sulfite will react with CD-3 to form some sulfonate, which is still a developer. This CD-3 Sulfonate will then reduce some more silver ions and then either react with another sulfite ion and become inactive, or react with dye coupler to form some oddball dye.

Donald Qualls said:

Testing by developing to B&W negative would be the simple way to arrive at correct first dev parameters, but a silver filter layer would require partial bleaching to make a negative visible for assessment. Most likely I'll have to do the whole process -- first dev, stop, wash, light fog, color dev, bleach, fix (or blix -- I have Flexicolor bleach and fixer, as well as RA-4 blix), wash, stabilize? -- to get film I can evaluate, then repeat with changes to the amount of halide solvent and time for the first dev, until it works right.

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That's one of the main issues with E-6 testing: each and every test run takes forever. I can nothing but look in pure awe at Stefan Lange's Homebrew thread - I have no idea how much time&effort went into these formulas, but it must have been massive.

BTW you save little money by using RA-4 CD, since you'd have to come up with some replacement for the E-6 FD as well, and whatever replacement you pick will have to be matched with your modified RA-4 CD to give decent slides. There are many variables in this process, and probably just one set of variables which works across several different E-6 materials.

Rudeofus said:

This is mostly correct, but if you mean "develop to completion" in E-6 CD step, it does not mean "until it runs out of dye couplers", but "until it runs out of developable silver ions", and this is the main point of Citrazinic Acid. It is a competitive coupler, i.e. oxidized CD-3 can couple either with a dye coupler, or with Citrazinic Acid. If you add enough Citrazinic Acid (or H Acid, or J Acid), all the developable silver ions will provide oxidized CD-3, which will then react with the Citrazinic Acid and produce no dye. If you add sulfite instead, the sulfite will react with CD-3 to form some sulfonate, which is still a developer. This CD-3 Sulfonate will then reduce some more silver ions and then either react with another sulfite ion and become inactive, or react with dye coupler to form some oddball dye.

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This does work with low sulfite levels, however, for RA-4 prints. We're talking a few ml. of, IIRC, a 10% sulfite solution in 300 ml of developer for an 8x10 drum (= a few hundred milligrams of sulfite). Any "oddball dye" that might form is lost in the correct dye, as long as the sulfite level is kept low (check Greg Davis, aka The Naked Photographer on YouTube, on the basics of RA-4 printing). Given what you've just told me about the citrazinic acid, however, I expect to have to add a small amount of peroxide instead, to reverse the effect of that color restrainer. Again, this is a matter of roundly one percent (give or take a factor of two or three) of 3% peroxide solution, meaning, again, tens of milligrams of actual hydrogen peroxide in 300 ml of developer.

That's one of the main issues with E-6 testing: each and every test run takes forever. I can nothing but look in pure awe at Stefan Lange's Homebrew thread - I have no idea how much time&effort went into these formulas, but it must have been massive.

BTW you save little money by using RA-4 CD, since you'd have to come up with some replacement for the E-6 FD as well, and whatever replacement you pick will have to be matched with your modified RA-4 CD to give decent slides. There are many variables in this process, and probably just one set of variables which works across several different E-6 materials.

Click to expand...

Don't know about "forever" -- mix/dilute first dev, dilute RA-4 color dev, put containers in water bath, set sous vide, go do something else for an hour or so. Come back, run through the process (45 minutes or so including all the wash steps?), hang the film, clean up, come back in several hours. It'll be about one test per day if I'm on vacation, one or two a week if I'm working. If the color dev doesn't work as expected, it'll only take one or two tests to know that; if it does, I expect to need between three and six tests to get the first dev right for the film I test with. First dev can be Dektol with thiosulfate added, possibly even Xtol (but probably not my replenished stock, since I might have to add something to it to get correct speed and proper Dmin and Dmax).

But you make it sound like I shouldn't bother, I should just spend $40+ to get an E-6 kit to process my five rolls of Ektachrome and call it a day. It's not that expensive (about 1/3 the cost of sending that many away). Or I should cross-process them in C-41 and live with the bizarre color shifts.

If you get a 2.5l kit, the cost per sheet or per roll should be substantially less than what you calculated here. You can store the concentrates (if gas blanketed with inert gas) for at least a year.

Well, that's the thing. I have five rolls of Ektachrome 100 (the pre-hiatus version) in 120 size, two exposed (years ago) and one in camera, and aside from those, the last time I shot Ektachrome was in a 126 SLR back in the mid 1980s (the slides are from Yellowstone, and last time I was there was about 1986). If it were convenient and economical to process my own, I might shoot more (for instance, it would open up Fuji chrome stocks in 4x5 vs. a single C-41 emulsion from Kodak, no other choices), but I'm not a chrome user on a normal day and likely won't ever be. It would take me much longer than a year to use up a 2.5L E-6 kit. If I have a way to process my occasional E-6 film with chemistry I'll already have on hand, then on the occasion when I need to shoot a roll, or a few sheets, of chromes, I can process them and be done. And with the ability to print the chromes via RA-4 reversal, I'm much more likely to want to expose and process them than I would have been previously.

If you use so little E-6 material, then a contracted color adjustment process is most likely not worth it. I do think, though, that you will end up liking the color palette of chromes ...

Oh, I've used Ektachrome a few times in the past. I shot a roll of Ektachrome (64?) in a Brownie Bullet around 1974, and got eight gorgeous 4x6.5 frames, despite using a simple camera, and I shot and (with the rest of my photography class) developed (E-4!) some sort of Ektachrome in a Kodak Reflex II in 1976; that time I had 12 6x6 frames that looked like you could crawl into them. As I said, I might well shoot more chromes once I get the reversal printing process dialed in. Seems to me I had a box of super slides around somewhere, from a 4x4 on 127 simple camera, as well.

One option for quickly getting the first dev in line would be to order only the first dev from Cinestill. Their E-6 offering, with the three first devs (standard, tungsten correction and increased dynamic range), prompts them to offer the first devs individually, so their kit users can try the options they didn't initially buy. Their first devs are only about $11/quart plus shipping (diluted from stock 1+1, good for up to 8 rolls from a quart). Knowing the first dev is right would let me adjust the color dev, if needed, then potentially use B&W film to explore getting the same gamma in the same time & temp and same pH to get a homebrew first dev that works the same.

Realistically, I only need to have it work correctly for about five film stocks -- Ektachrome 100, two Velvias, Provia, and maybe Crossbird. I'd be happy enough if it needed a different first dev for each.