debug my RA4 process? (insane contrast)

[Photo Engineer]

The bleach and fix portions of the blix were designed to work together in conjunction with each other. If separated, they will give the results you show. It is retained silver and is akin to bleach bypass. See the reduced saturation in the reads and yellows?

PE

 

[polyglot]

Certainly seems so, PE. Does one need to buy different chemistry to use separately as you suggest in post #7?

At least I have a repeatable way of generating the effect when desired!

 

[Photo Engineer]

I suggest that you use a real, 2 part blix designed for paper. That is best.

PE

 

[stefan4u]

Dear polyglot.

I’m not completely sure about, but I suspect an elevated pH in the bleaching solution if the “Fixer part” is missing. The “Fixer part” usually/often contains sodiumbisulfite and/or acetic acid to maintain a acidic milieu. Depending on used product the pH of the complete Blix should be slightly acidic around pH 5.5 till about 6.

Maybe a bleach accelerating Agent is missing too (something like mercaptotriazole), but this would be more for film blixes, I think…

Kodak RT BLIX works fine if the original “Fixer Part” is substituted by a liquid acidic BW Fixer (Tetenal Superfix). This Superfix does (naturally) NOT contain bleach accelerators or silver solvents, but shifts the pH to the acidic side and boosts bleaching activity.
If you wanna stay with separated Bathes (without having separated solutions designated for this) I would simply try to add some acetic acid (in increments) to your bleach and watch it’s activity.

Hypothetical: Try to omit the rinse step after (a boosted) stop bath (add about 10-20g sodiumbisulfite per Liter to your 2% acetic acid. More free acid and makes developer residues soluble. Caution, irritating sulfur fumes may release).
The inherited acid in the drum (you do drum processing, don’t you?) could be enough to lower the pH the necessary bit in the following bleach step.

Or simply stay with the original BLIX solution, this would save time and trouble …

Regards, Stefan

 

[polyglot]

Stefan: I'm pretty sure you're right; there's something in the fix that is accelerating the bleach or permitting the reaction to progress to a different equilibrium. I could easily believe that a change in pH would cause a shift in the reaction equilibrium such that there is metallic silver remaining.

Running it as a blix isn't really a problem for me, I just keep a small quantity of working solution (about 400mL) and if that dies, it's no great loss. I replenish working solution from separate bleach & fix solutions which should avoid the problem of the bleach killing the fixer while they're on the shelf. And of course the process is faster than running them separately.

 

[Photo Engineer]

All bleaches must rely on something to shift the reaction to the right (Ag+) and thus the fix portion does that! In Bleaches, they supply something else. Anyhow, you need 2 pars to a bleach or blix.

PE

 

[polyglot]

The C41 and E6 bleaches I have are only 1-part concentrates and they're very clear in the instructions that the bleach should not be permitted to contaminate the fixer. Bleaching is therefore complete before fixing begins.

I thought RA4 would be formulated similarly but apparently not in this case.

 

[hrst]

The C41 and E6 bleaches I have are only 1-part concentrates and they're very clear in the instructions that the bleach should not be permitted to contaminate the fixer. Bleaching is therefore complete before fixing begins.

I thought RA4 would be formulated similarly but apparently not in this case.

RA-4 process uses a blix. C-41 and E6 use separate bleach and fix. C-41 and E6 bleach and fix are not formulated to be mixed. RA-4 blix components are formulated to be mixed, and they are NOT called "bleach" and "fix", even though their main ingredients are the same.

RA-4 blix is provided in two parts that are supposed to be mixed as per instructions. This is for longer shelf life if the products end up sitting on the shelf before mixing. These parts are NOT bleach and fix. RA-4 process uses a blix. You CAN use a separate bleach and fix for RA-4 paper too, but the two parts of the blix are not those.

When in doubt, just follow the instructions . The official blix works perfectly. Maybe you have said this already and I missed it, but why add more steps?

 

[RPC]

RA-4 process uses a blix. C-41 and E6 use separate bleach and fix. C-41 and E6 bleach and fix are not formulated to be mixed. RA-4 blix components are formulated to be mixed, and they are NOT called "bleach" and "fix", even though their main ingredients are the same.

RA-4 blix is provided in two parts that are supposed to be mixed as per instructions. This is for longer shelf life if the products end up sitting on the shelf before mixing. These parts are NOT bleach and fix. RA-4 process uses a blix.You CAN use a separate bleach and fix for RA-4 paper too, but the two parts of the blix are not those.

I am aware it is common terminology, but all the Kodak literature I have ever seen never uses the term "blix", but always "bleach-fix". I believe the term "blix" was originated and used by another company for the same thing. Someone correct me if I am wrong. Just thought I would mention this to avoid confusion for the beginner or uninformed.

 

[Photo Engineer]

Kodak used the term Blix internally and were prepared to release it under that name. A visitor from another company saw a pre-release bottle of the Blix and carried that thought back to his company. That other company copyrighted the name and Kodak was barred from using it.

The term Bleach-Fix was used for all external products, but internally we still used Blix. In fact, the first RA-4 Bleach Fix formula was transmitted under the name Blix 1066 (1066 being the date of the notebook entry of that formula).

A bleach contains a counter ion to assist in the bleaching action. Thus you have a Rehal bleach when you mix Ferricyanide and Bromide. It does not work well without the halide. A bleach is therefore self contained in terms of all ingredients.

In a blix, the fixing part is used as part of the driving force for the oxidation. Thus part of the driving force is absent unless you mix the two parts. They are sold as two parts to prevent deterioration of the fixer part during keeping.

PE

 

[polyglot]

Some more progress: I did a couple of test rolls (Ektar, Reala) with development pulled one stop (2:45 instead of 3:15). That mostly makes up for the high contrast of the paper (Crystal Archive) and means I can now make portraits that don't look like they were shot on RVP50 or worse.

My long-suffering model+wife:

The print looks better than this scan of it; my new V600 seems to have a crap Dmax at least on this lustre paper. The contrast & saturation of the print is slightly lower than what you see here.

Contrast and saturation are still in the high/glamour range rather than anything subtle but it's getting close to workable for skin-tones and after all, this is Ektar.

One observation: when pulling C41 development, you don't really need to increase exposure much at all. I shot a sequence at EI100, EI50, EI25 and EI6. The EI100 still had plenty of shadow detail, especially considering that the print-exposure required to not blow highlights will not include the deepest shadows recorded on the neg.

Second observation: under-exposing RA4 can cause nasty skin-tones in the highlights, presumably because one dye channel goes into the shoulder while the others are still on the straight-line.

 

[Chris Douglas]

Are you using a condenser enlarger? I tried and got too much contrast.

 

[polyglot]

No, a DeVere 504. Diffusion.