Formulating cold tone paper developers

Ian Grant · Apr 1, 2009

In addition the use of Potassium Iodide as the restrainer will give much Bluer tones, however this might be at the expense of archival permanence, I'm just reading some research by Grant Haist.

But this does lead to the possibility of a bleach / redevelopment process for "Blue" tones using a KI based re-halogenating bleach & re-developer.

Ian

Peter Schrager · Apr 1, 2009

cold tones

it just seems from my own personal research that the paper you use is far more suseptible to tones than the developer is usually capable of...try slavich with something like zone VI and add benzo...freezing cold!! most of the formulas worked well for the older papers but have little or no effect on modern ones...
Best, Peter

Tom Kershaw · Apr 1, 2009

Peter,

As far as I'm aware the Slavich papers are not distributed in the UK, or generally in the EU.

Tom.

Tom Kershaw · Apr 1, 2009

Earlier today I mixed up my proposed formula (Experimental Cold Tone Paper Developer V.2.0) which works well at 1+3 dilution, and produces strong blacks with Kentmere Bromide, good contrast and tonality etc. However, I would not classify the tones as blue-black. I then added 1g Benzotriazole to the working solution which seemed counter productive, and resulted in odd changes in tonality and contrast.

The ID-62 developer with reduced Potassium Bromide and the addition of Benzotriazole in 20, + 10, + 20, + 30, + 20ml increments produced similar results to my altered D-72. The tone was slightly warmer before the addition of Benzotriazole and resulted in similar problems to E.C.T.P.D v2 at higher concentrations of Benzotriazole.

Tom Kershaw · Apr 1, 2009

Ian Grant said:
In addition the use of Potassium Iodide as the restrainer will give much Bluer tones, however this might be at the expense of archival permanence, I'm just reading some research by Grant Haist.

But this does lead to the possibility of a bleach / redevelopment process for "Blue" tones using a KI based re-halogenating bleach & re-developer.

Ian

Ian,

In what sort of quantities would you suggest adding Potassium iodide in a single bath development scenario?

If using a bleach and redeveloping technique does the Potassium iodide still introduce potential stability concerns?

Tom.

Tom Kershaw · Apr 1, 2009

The MSDS for Harman Cooltone lists DTPA, Hydroquinone, and Potassium Carbonate. Presumably the DTPA is used to deal with water quality issues. However, would the use of Potassium Carbonate in place of Sodium Carbonate alter print tone?

http://www.freestylephoto.biz/pdf/msds/ilford/Ilford_Cooltone_Developer.pdf

http://en.wikipedia.org/wiki/DTPA

Tom.

Tom Kershaw · Apr 1, 2009

Further research on APUG suggests Slavich Unibrom is available in Germany from www.monochrom.com

Tom.

Ian Grant · Apr 2, 2009

Tom, Ilford and Agfa (and presumably Kodak in liquid Dektol) use Potassium Carbonate often with Sodium or Potassium Hydroxide in place of Sodium Carbonate in liquid developers. A typical Ilford example (Patent reference developer) uses 38.44g Potassium Carbonate plus 2.12g of Sodium Hydroxide per litre instead of 50g of Sodium Carbonate, while a similar Agfa formula uses 15 g Potassium Carbonate and 4g Potassium Hydroxide. It's all to do with the relative insolubility of Sodium Carbonate being the limiting factor of the potential concentration of a commercial developer, and also cost savings.

Adding Potassium salts instead of Sodium will give very slightly warmer tones.

If you add Potassium Iodide then Kodak's research was into 1-8gm's per litre of working solution, but the KI has an impact on fixer capacity as Silver Iodide is formed which is relatively insoluble. Kodak were using it in activators with developer incorporated papers to control image colour and induce blue B&W tones.

Ian

Tom Kershaw · Apr 2, 2009

Ian,

Aside from using Potassium Iodide to induce blue-black tones, do you have any other suggestions or formulation approaches to produce blue-black tones?

Tom.

Ian Grant · Apr 2, 2009

I'm looking into that at the moment, but I'll be in a better position next week when I can access my reference books.

A major problem is that Ilford & Agfa used proprietary organic agents to control the cold/blue tone, even if we knew what they are it might be difficult to get the small quantities required.

As soon as I find something I'll post it here.

Ian

Anscojohn · Apr 2, 2009

Freestyle offers a liquid concentrate cold-tone paper developer, stating dimezone-s as one of the constituents.

Ian Grant · Apr 2, 2009

Ilford now use Dimezone-S in some of their liquid PQ developers instead of Phenidone so it shouldn't make any significant difference to the image colour/tone.

Ian

Tom Kershaw · Apr 2, 2009

Ian,

What do you think the effect would be of using say 8g Benzotriazole in the stock solution, translating into 2g per litre of working solution? I suspect the paper would need to be given extra exposure under the enlarger.

Tom.

EDIT: Actually, I've tested at 1.5g Benzotriazole per litre of working solution already...

Ian Grant · Apr 2, 2009

There are too many variables Tom, different papers will behave in different ways, you'd need to try it. I have to admit that most of my research in the past regarding image colour has been predominantly into warm-tone developers and toners.

Ian

nworth · Apr 13, 2009

First, let me state that I don't really know what I'm doing. But the principles laid out here seemed so clear: for cold tones keep the pH high (within reason), avoid phenolic developing agents, use plenty of restrainer, but substitute potassium iodide and benzotriazole for potassium bromide. It couldn't be that hard. After searching a good many published formulas, I came up with the following and mixed it up using incantations that have proved effective in previous such adventures:

Sodium sulfite (anh) 15 g
Trisodium phosphate 40 g
Phenidone 200 mg
Ascorbic acid 10 g
Potassium iodide (1% soln) 5 ml
Benzotriazole (1% soln) 10 ml

pH 10.8

(Sodium carbonatre and sodium hydroxide could probably be substituted for the TSP to get this pH. The TSP I used was a commercial cleaning material, and its hydration is uncertain.)

I tried it out with Ilford MGIV RC. That paper isn't known for its tonal response with different developers, but oh well. I compared the results with development in D-72. The results were somewhat cooler, although not a lot. This developer obviously needs tuning, since the midtones were decidedly worse than those with D-72. In any case, I was encouraged. I tried the following:

Metol 3 g
Sodium sulfite (anh) 15 g
Trisodium phosphate 40 g
Ascorbic acid 10 g
Potassium iodide (1% soln.) 10 ml
Benzotriazole (1% soln.) 20 ml

The results were much improved. The tone shifted very significantly toward the blue, contrast was good and reasonable, and the gradation was a lot more like D-72. The principles seem to work, at least from these limited tests. My curiosity was satisfied, so I quit here. But the developers are not really finished. They need fine tuning. Unfortunately, that's hard work.

Ian Grant · Apr 13, 2009

Now found references to 3 suggested adjuvants all of which should be better at producing Blue tones than Benztriazole, one is a halide , plus a variable Purple-black, Blue-black, Blue, Violet formula which I'll test in the next few days. Much work was done in this field in the 20's & 30's.

Ian

thmm · Apr 13, 2009

Ian Grant said:
plus a variable Purple-black, Blue-black, Blue, Violet formula which I'll test in the next few days.

That sounds extremely interesting, please post your results!

Ian Grant · Apr 14, 2009

Additive-X

thmm said:
That sounds extremely interesting, please post your results!

I did a crude test last night with some Ilford Warmtone FB and the difference in colour was quite distinct.

The left side was developed in the PQ version of ID-20 (Forte FD-203 which is ID-62 with no benzotriazole), the right with the same developer with Additive-X.

However Additive-X which is Thiourea (Thiocarbamide) is problematic, the idea is attributed to S.H. Wratten (1910). The Thiourea causes fogging so the developer needs to be well restrained.

So 10ml of 1% Thiourea in 400ml working solution of developer resulted in almost instant fogging. Cutting the amount of Thiourea drastically adding 10ml of a 0.005% solution and 100ml of 1% Benzotriazole as the anti-foggant gave the results above. The colour shift was caused by the Thiourea, I tried first with no Bezotriazole) which I added to cut the slight base fog.

This initial crude test shows there's definitely some potential in adding Thiourea, but more work needs to be done.

Another chemical suggested by I.G. Farbenindustrie (Agfa) to produce cold blue tones is Sodium Fluoride, at 0.4% in the developer formula, but as fluoride is classed as a Poison it's probably got to be ruled out.

More usually organic compounds have been used, mostly proprietary, starting with quinine hydrochloride, quinoline is said to be amongst the best but has a strong unpleasant smell. Agfa and Ilford Patents show their searches for alternatives.

Ian

mikebarger · Apr 14, 2009

Thanks Ian, that is a great test and demo.

Mike

Kirk Keyes · Apr 14, 2009

Peoples -

Do not allow thiourea to come in contact with your skin. See:
http://www.jtbaker.com/msds/englishhtml/t3107.htm

Health Rating: 2 - Moderate (Poison)
Flammability Rating: 1 - Slight
Reactivity Rating: 1 - Slight
Contact Rating: 3 - Severe (Life)
Lab Protective Equip: GOGGLES & SHIELD; LAB COAT & APRON; VENT HOOD; PROPER GLOVES

"Investigated as a tumorigen, mutagen, reproductive effector."

It also says it is an anticipated carcinogen.

You can get cold tones similar to Ian's example using Ansco 130 with benzotriazole substituted for the bromide.
Also, benzotriazole is not known or suspected as a carcinogen, it has a Health Rating of 1, and a Contact Rating of 2. Much safer than thiourea...

thmm · Apr 14, 2009

Ian Grant said:
However Additive-X which is Thiourea (Thiocarbamide) is problematic, the idea is attributed to S.H. Wratten (1910). The Thiourea causes fogging so the developer needs to be well restrained.

So 10ml of 1% Thiourea in 400ml working solution of developer resulted in almost instant fogging. Cutting the amount of Thiourea drastically adding 10ml of a 0.005% solution and 100ml of 1% Benzotriazole as the anti-foggant gave the results above. The colour shift was caused by the Thiourea, I tried first with no Bezotriazole) which I added to cut the slight base fog.

Hmm, that's very interesting! My uneducated guess would have been that thiourea would be very hard to restrain.
I suppose such a formulation would be a one-shot developer and sulfide toner (certainly convenient!), or is something entirely different going on here?

Ian Grant said:
Another chemical suggested by I.G. Farbenindustrie (Agfa) to produce cold blue tones is Sodium Fluoride, at 0.4% in the developer formula, but as fluoride is classed as a Poison it's probably got to be ruled out.

Well, my toothpaste contains a third of that amount, just for comparison. But of course, getting the fluoride would be hard for mere hobbyists like me...

Ian Grant said:
More usually organic compounds have been used, mostly proprietary, starting with quinine hydrochloride, quinoline is said to be amongst the best but has a strong unpleasant smell. Agfa and Ilford Patents show their searches for alternatives.

Hmm, quinine HCl would even be available from chemist's shops over here...

Very interesting, thanks for posting your research!

Ian Grant · Apr 14, 2009

Kirk Keyes said:
Peoples -

Do not allow thiourea to come in contact with your skin. See:
http://www.jtbaker.com/msds/englishhtml/t3107.htm

Health Rating: 2 - Moderate (Poison)
Flammability Rating: 1 - Slight
Reactivity Rating: 1 - Slight
Contact Rating: 3 - Severe (Life)
Lab Protective Equip: GOGGLES & SHIELD; LAB COAT & APRON; VENT HOOD; PROPER GLOVES

"Investigated as a tumorigen, mutagen, reproductive effector."

It also says it is an anticipated carcinogen.

You can get cold tones similar to Ian's example using Ansco 130 with benzotriazole substituted for the bromide.
Also, benzotriazole is not known or suspected as a carcinogen, it has a Health Rating of 1, and a Contact Rating of 2. Much safer than thiourea...

Kirk, most chemicals used in Photography are hazardous if used incorrectly, many far more so than Thiourea. The level of Thiourea used is extremely low and so not a potential problem, a great many photographers will be using Thiourea at far higher concentration in Sepia toners.

Agfa Ansco 130 isn't really a substitute to get Blue/Black tones, and anyway Glycin isn't available in the UK and EU and hasn't been for a number of years, so it needs another approach.

thmm said:
Hmm, that's very interesting! My uneducated guess would have been that thiourea would be very hard to restrain.
I suppose such a formulation would be a one-shot developer and sulfide toner (certainly convenient!), or is something entirely different going on here?

Something different is definitely going on, you'd expect Thiourea to give warmer tones but it's doing just the opposite.

Ian

thmm · Apr 14, 2009

Ian Grant said:
Agfa Ansco 130 isn't really a substitute to get Blue/Black tones, and anyway Glycin isn't available in the UK and EU and hasn't been for a number of years, so it need[s another approach.

It is available from a company called Fototechnik Suvatlar via Wolfgang Moersch (see http://www.moersch-photochemie.de/content/rohchemie, sorry, only in german). Just in case someone is looking for it...

Ian Grant said:
Something different is definitely going on, you'd expect Thiourea to give warmer tones but it's doing just the opposite.

Hmm, I have seen warm tone papers get colder (violet-brownish) in sulfide, and assumed that was what had happened there. Very interesting!

Kirk Keyes · Apr 14, 2009

Ian Grant said:
Kirk, most chemicals used in Photography are hazardous if used incorrectly, many far more so than Thiourea.

Something is "hazardous" regardless of how it's used. It's an intrinsic property of the substance. The amout of risk or exposure varies based on the practice of the individual using it.

I just want to point out that thiourea is a suspected carcinogen (unlike the vast majority of photochemicals typically used in the home darkroom) and people should be aware of it.

That said, I've used thiourea toner myself, so I'm not saying it's something to never use, I'm just saying it's something that people need to have some understanding of the potential hazards when using thiourea.

Kirk Keyes · Apr 14, 2009

Ian Grant said:
Agfa Ansco 130 isn't really a substitute to get Blue/Black tones,

The benzotriazole variation of Ansco 130 that I mentioned above certainly does change the tone of Ilford Warmtone FB paper, and much as you show in your scans above. No thiourea needed to make a nearly neutral paper considering how warm it is to start with.

Could you take some color densitometer readings of some paper in your formula at Dmax and compare them to the same paper in regular developer so we can get an idea of the color shift?

Formulating cold tone paper developers

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