Some RA-4 Reversal success today...

[Rudeofus]

What would be the suggested procedure if mottling happens? Change paper type, or change FD composition until mottling is no longer visible?

 

[Photo Engineer]

There was never a reliable solution for R prints and I found none in my RA4 reversal work. I used busy scenes to mask it. Scenes with a large uniform color and surface wore the worst.

PE

 

[peoplemerge]

"Working strength [PQ UNIVERSAL] left in an open dish should not be kept for more than one working day. If stored in a tightly capped bottle they may last up to 24 hours." - Ilford "TECHNICAL INFORMATION B&W PAPER DEVELOPERS."
Keeping working solution for 9 months does add some variables.
"A 1 litre bottle of PQ UNIVERSAL developer makes enough working strength solution at 1+9 to process 700 20.3x25.4cm (8x10in) sheets of RC"
I figure that makes 10x 1L solutions each with the capacity of 70 sheets. I can't think of a time I've printed even half that many sheets in a 2 day period. Of course, the effectiveness will degrade somewhat over the course. Linearly?

It would be nice to have a starting point of proportions PQ MSDS as a starting point. I can order some Dimezone-S and experiment if someone wants to take a stab at proportions:
Dimezone-S
Distilled water or chelating agent
HYDROQUINONE
Potassium Carbonate

Then can try adding a few g/L bromide. Or using Phenidone in place of Dimezone-S because it seems like more photrioers might have it on shelves.

 

[mnemosyne]

"Working strength [PQ UNIVERSAL] left in an open dish should not be kept for more than one working day. If stored in a tightly capped bottle they may last up to 24 hours." - Ilford "TECHNICAL INFORMATION B&W PAPER DEVELOPERS."
Keeping working solution for 9 months does add some variables.
"A 1 litre bottle of PQ UNIVERSAL developer makes enough working strength solution at 1+9 to process 700 20.3x25.4cm (8x10in) sheets of RC"
I figure that makes 10x 1L solutions each with the capacity of 70 sheets. I can't think of a time I've printed even half that many sheets in a 2 day period. Of course, the effectiveness will degrade somewhat over the course. Linearly?

It would be nice to have a starting point of proportions PQ MSDS as a starting point. I can order some Dimezone-S and experiment if someone wants to take a stab at proportions:
Dimezone-S
Distilled water or chelating agent
HYDROQUINONE
Potassium Carbonate

Then can try adding a few g/L bromide. Or using Phenidone in place of Dimezone-S because it seems like more photrioers might have it on shelves.

Why not for a start simply use fresh PQ at 1+9 plus potassium bromide to season it. Do a series of tests with increasing additions of bromide until you hit the sweet spot? This would be my best bet. We know PQ worked (at least once), so why complicate things and adding more variables by trying to replicate the developer formula.

 

[peoplemerge]

@mnemosyne true, can try that as I wait for the base chemical to arrive.

 

[Mainecoonmaniac]

Looks beautiful. Beats doing an interneg. But since is RA4, is the contrast is lower than Cibachrom or to old Kodak R-200 process?

 

[peoplemerge]

Contrast is extremely high, but it's possible to reduce it by adjusting the color developer (RA4 chemicals). One of the links I posted earlier this thread has a elaboration by PE.

 

[Rudeofus]

It would be nice to have a starting point of proportions PQ MSDS as a starting point. I can order some Dimezone-S and experiment if someone wants to take a stab at proportions:
Dimezone-S
Distilled water or chelating agent
HYDROQUINONE
Potassium Carbonate

Then can try adding a few g/L bromide. Or using Phenidone in place of Dimezone-S because it seems like more photrioers might have it on shelves.

Here is what you could start with (working solution, not concentrate): 1 g/l Hexametaphosphate (=Calgon. You'll need a sequestering agent at this pH, and Calgon is cheap and good enough if long shelf life is not important), 0.2 g/l Phenidone (don't bother with the more expensive Dimezone-S unless you want to store the solution), 2-3 g/l HQ, 5 g/l Sodium Carbonate (potassium salt only needed if you make a concentrate), 20-30 g/l Sodium Sulfite (necessary in any developer using HQ, no idea how Ilford got away with not listing it in the MSDS).

Once you got this mixed, put in a sheet of unexposed B&W paper (darkroom light). If it fogs, add first up to 1 g/l KBr, then as needed Sodium Bicarbonate until it doesn't. Turn on the room light and verify that it develops as fast as the original. You should now have something, which most likely isn't, but at least somewhat resembles Ilford's PQ dev.

 

[bvy]

Why not for a start simply use fresh PQ at 1+9 plus potassium bromide to season it. Do a series of tests with increasing additions of bromide until you hit the sweet spot? This would be my best bet. We know PQ worked (at least once), so why complicate things and adding more variables by trying to replicate the developer formula.

Welcome to how I spent my Sunday afternoon. Using freshly mixed PQ developer (always one shot) I did a series of test prints adding varying amounts of potassium bromide. My results are below. The original print is in the upper right. The "control" print is in the upper left, and I can reproduce this result pretty consistently using fresh PQ at 1+9. The bottom images introduce potassium bromide in the indicated amounts. I was able to get reasonably close to my original print at the 1.5+60 dilution, and I wonder if the only difference now is some exposure. I should mention, all other variables were kept the same -- in particular, filtration and exposure (35M+40Y, f/4 at 18").


This approach does seem to have a positive effect on mottling. By way of comparison, here's an older test print using fresh PQ at 1+17.5. The mottling is excessive.


Finally, pardon the uneven development in some of these. I'm processing in drums and using the minimum amount of first developer to try to economize since my supply of PQ is quickly vanishing from all this experimenting!

 

[Photo Engineer]

Looks like Bromide is your answer.

PE

 

[halfaman]

View attachment 194379

I am following this thread with great interest. I don't understand thw notation used in the photos for dilution and salt addtion. 1+9 - 75 ml + 1.5 gr KBr??? ml of what?? gr are per liter??

Can you clarify, bvy? Thanks in advance.

 

[bvy]

I am following this thread with great interest. I don't understand thw notation used in the photos for dilution and salt addtion. 1+9 - 75 ml + 1.5 gr KBr??? ml of what?? gr are per liter??

Can you clarify, bvy? Thanks in advance.

That's 60ml (or 75ml) of PQ 1+9 to which I added 1.5g of (solid) potassium bromide. I have a 1.5g measuring spoon, and it's easier to vary the amount of liquid. Sorry if I'm mixing units.

 

[mnemosyne]

Thank you! That looks promising. Relatively small variations in the concentration of KBr apparently make quite a difference in the result ...

 

[halfaman]

That's 60ml (or 75ml) of PQ 1+9 to which I added 1.5g of (solid) potassium bromide. I have a 1.5g measuring spoon, and it's easier to vary the amount of liquid. Sorry if I'm mixing units.

Thanks for the clarification! I hope I can try it myslef in short term.

 

[bvy]

These may be my best results yet. Unfortunately it entailed burning several sheets of fresh paper to manually exhaust small amounts of developer. The top image is 60ml of developer (PQ 1+9) in which I developed two full 8x10 sheets of Ilford RC paper (so 1/30). The bottom is 72ml of developer and three sheets (1/24). The paper was fully exposed to room light and tray developed over two minutes.

The bottom image may be the sweet spot. The contrast is even better than the original shown in the first post -- there's shadow and highlight detail not visible there. The whites are just as white, not too gray or dark. And the mottling is very much under control.

So now what? I'm not getting results like this with the addition of bromide. Black and white paper isn't expensive, but for these purposes, it isn't cheap either. When I bumped the exhaustion rate up to 1/20, I tried making a full 8x10 print instead of the 4x5's I've been making. The result (not shown) was uneven and flat. At first I thought that rate of exhaustion might be too much (and that might still be the case) but now I'm thinking it's because I quadrupled the surface area of the print I made, exhausting the developer even more. So I estimate 12 8x10 sheets of paper to make one 8x10 color reversal print. Maybe I can make an offer for some of that paper on eBay where the seller does us the favor of photographing it.

 

[iandvaag]

Great results, and thanks for documenting the process for us. I have one idea, not sure if it is any good. What if you replenished your developer, rather than use it one shot? This way, as you are printing, you could do a simple replenishment (remove X mL of used working solution and add in X mL of fresh working solution) and maintain a certain level of exhaustion, without having to waste a bunch of b&w paper. The big "if" is if the color paper exhausts the developer in a similar manner to the b&w paper. I suspect there will be differences, as color papers are high chloride emulsions while enlarging b&w papers have a higher bromide content (bromide being a stronger restrainer than chloride.) It would certainly involve more testing, which you may be getting tired of. Just a thought. I'm not sure if replenishment would be possible, the developer might be too oxidized since you are using drums, but developer oxidation is what you're after, right?

The only thing else I can think of is what I mentioned previously: using a KBr + Kferricyanide bleach on the b&w paper that you used to season the developer, allowing the paper to be redeveloped to further exhaust the developer.

 

[jtk]

There was never a reliable solution for R prints and I found none in my RA4 reversal work. I used busy scenes to mask it. Scenes with a large uniform color and surface wore the worst.

PE

Certainly there WAS a reliable way to make exquisite R prints...it involved good process control and flashing. Masks weren't necessary.

 

[jtk]

This is really impressive. The skin tones in particular are very nice - way better than any other examples I've seen. The contrast looks very similar to what I used to get with Cibachrome, when just doing a straight print without any dodging or masking. Highlights were similarly blown out. The top left corner seems to show some mottling, or is that just an effect of the lighting?

How would you compare this to a print from an internegative, either done in the darkroom or with a slide copier attached to a camera?

Large format interneg is the best way to make fine color prints from slides, assuming one is superstitious about scanning and inkjet. Still, one can make surprisingly fine internegs using virtually any color negative film in a slide-duplicating setup. I've done it with 6X7. When contrast is a problem all one needs to do is pre-flash (e.g. 1/16th stop...bracket exposure).

 

[Photo Engineer]

Certainly there WAS a reliable way to make exquisite R prints...it involved good process control and flashing. Masks weren't necessary.

The prints must have been on FB paper then to eliminate mottle. All the prints on RC that I saw were mottled in uniform color areas.

As for flashing, it may fix some contrast problems but not color error and that is only one problem.

PE

 

[Craig]

Oh, and Ilfochrome is not coated on RC.
PE

Some was. There was the classic polyester base and an RC base. Polyester was called Ilfochrome deluxe, RC was called Ilfochrome paper.

 

[Photo Engineer]

Very little in the US. The bleach bath tended to delaminate the RC support from the edges inward. In fact, we never saw the paper version.

PE

 

[DREW WILEY]

There was an RC version of Ciba/Ilfochrome called Pearl. Same chromolytic dyes but satin sheen, less expensive. They also briefly marketed an unrelated actual RA4 paper in Europe, not here.

 

[DREW WILEY]

Just noted the intermediate post. I did some printing on Ciba RC. No delamination. The prints still look good 30 yrs later. Maybe high temp 2 min commercial quickie processing in P3X did that. I used 3min per step standard P3. The most beautiful product I ever got from them was on polyester base but with flawed gelatin which came out with a wonderful lustre and not the usual mirror shine. They had no idea exactly what happened and could not replicate it.

 

[bvy]

Great results, and thanks for documenting the process for us. I have one idea, not sure if it is any good. What if you replenished your developer, rather than use it one shot? This way, as you are printing, you could do a simple replenishment (remove X mL of used working solution and add in X mL of fresh working solution) and maintain a certain level of exhaustion, without having to waste a bunch of b&w paper. The big "if" is if the color paper exhausts the developer in a similar manner to the b&w paper. I suspect there will be differences, as color papers are high chloride emulsions while enlarging b&w papers have a higher bromide content (bromide being a stronger restrainer than chloride.) It would certainly involve more testing, which you may be getting tired of. Just a thought. I'm not sure if replenishment would be possible, the developer might be too oxidized since you are using drums, but developer oxidation is what you're after, right?

The only thing else I can think of is what I mentioned previously: using a KBr + Kferricyanide bleach on the b&w paper that you used to season the developer, allowing the paper to be redeveloped to further exhaust the developer.

Interesting idea, and I had considered it. But I think this takes me even further down the road of exhausting the developer in hard to reproduce ways (for reasons you mention). As far as oxidation, it's nothing that I'm interested per se -- except perhaps insofar as it contributes to (or contributed to) the final result. But it would be the hardest to reproduce consistently of all the variables described, so I'm happy to eliminate it from the equation if possible.

I seem to be getting desirable results from quickly exhausting fresh developer with fresh paper. I just need to figure out what additives and in what amounts take the place of fresh paper.

 

[halfaman]

So now what? I'm not getting results like this with the addition of bromide.

Why not continue decreasing the ammount of KBr content? You may have to prepare bigger batches in order to be able to control it, but I would not drop that way. You have tried 25 gr/l (60 +1.5) and 20 gr/l (75+1.5) with a clear improvement to my eyes with less bromide, you can continue dropping the quantity to 15 and 10 gr/l...