Ammonium Thiosulfate toning - I need help

greenspun.com : LUSENET : B&W Photo - Printing & Finishing : One Thread

I've been trying to tone prints with a mix of Ammonium Thiosulfate and Sodium Hydroxide for getting yellowish/brownish tones but this resulted in a complete failure. Can anybody out there help understand what I did wrong ?

My tries were made with Forte Polywarm Tone and Ilford Multigrade IV. The bleaching was made with Ferry (100 grams in one liter for the stock solution, then diluted 1 + 20) for 1 1/2 minutes. For the toning solution, I used 70 mg of Thiosulfate + 30 mg of Hydroxide in one liter, both from stock solution of 100 g/Liter. Everything was at 20 Celsius and I washed the prints after each step.

The bleaching was apparently OK, although I had never bleached prints before, so I don't have experience for knowing for sure, but in the toning solution, absolutely nothing happened, although I left the prints for a good 10 minutes.

Thks in advance for your help.

-- Pascal Quint (quint.pascal@wanadoo.fr), December 09, 2001

Answers

I'm not familiar with the formula for such a toner.

-- Ed Buffaloe (edb@unblinkingeye.com), December 09, 2001.

That formula sound suspicious. Sepia toners typically use a rehalogenating bleach - ferricyanide and pottasium bromide is the usual soup, followed by a toning bath, which is typically sodium sulfide or thiocarbamide. It sounds to me like you used a ferri bleach bath. The following bath of ammonium thiosuphate (and sodium hydroxide) would have fixed out the image i.e., the thiosulpahte would have dissolved the silver grains. Good luck, DJ.

-- N Dhananjay (dhananjay-nayakankuppam@uiowa.edu), December 09, 2001.

Pascal:

The formulae you give would not be used as a toner, but rather, as a reducer. The image would be either reduced in density or removed totally.

-- Ken Burns (kenburns@twave.net), December 09, 2001.


Ammonium Thiosulfate toning - one more question

Thanks for your answers. If I understand correctly, the problem comes from the Ammonium Thiosulfate. In previous discussions, I noticed that people use "Thiocarbomide" with Sodium Hydroxide. I thought thiocarbomide and ammonium thiosulfate were the same chemicals... Sorry I'm not a chemist at all ! I'm trying to identify exactly which components I need, so allow me one more question : is thiocarbomide the same as "thiorea" ?

Thks

-- Pascal Quint (quint.pascal@wanadoo.fr), December 10, 2001.


I've never used this but someone told me to use thiocarbamide with sodium hydroxide to achieve a tone that might be described yellowish/brownish.

-- Nigel Smith (nlandgl@unite.com.au), December 10, 2001.


thiourea = thiocarbamide

-- wdnagel (wdnagel@home.com), December 10, 2001.

Yes, they are the same chemical and Thiocarbamide toner gives beautiful brownish tones that vary according to the dilution and can be much more interesting than the ones of the (stinking) sulphide sepia toner...

-- George Papantoniou (papanton@hol.gr), December 10, 2001.

Pascal:

Thiocarbamide and ammonium thiosulfate are NOT the same chemical and are NOT interchangeable. I use thiocarbamide for all my sepia toning because it does not have the highly objectionable odor of sodium sulfide. Again, thiocarbamide and ammonium thiosulfate are not the same thing.

-- Ken Burns (kenburns@twave.net), December 10, 2001.


Greetings,

All of the information you received so far is correct, but I'd like to add one thing, particularly if you're going to use thiocarbomide. I believe thiocarbomide (a.k.a. thiourea) is a known carcinogen and just beacuse it doesn't smell as bad, doesn't mean it should not be treated with respect.

Regards,

-- Pete Caluori (pcaluori@hotmail.com), December 10, 2001.


Moderation questions? read the FAQ