Questions about sulphide toning

[Claire Senft]

I recently toned a number of fiber glossy prints. The peints were on a neutral paper. The prints, as is my normal practice were received hypo eliminator and and very complete washing by being constantly hand shuffled thru ten five minute cycles in a tray with dump and refill of water being used.

Because I am now leaning to be more conservative in trying to achieve a the best LE possible I decided to completely sulphide tone these prints. I am happy with appearance of the results. Here is what I did:

Rewetted the prints for 1/2 hour. approximately 10 minute bleaching in the following:.
1 liter of tap water, 50grams of potassium ferricyanide, 25 grams of potassium bromide. Several prints were constantly being shuffled at a time until it appeared that all bleaching was completed. Then they were rinsed an put into a holding bath of plain tap water until all of the prints were bleached. Then they were washed by hand shuffling for 1/2 hour in 75ºF water.
Then I mixed the following redeveloping toner:
Thiourea 2 grams
washing soda 100 grams
1 liter of water.

The prints were again hand shuffled for about 8-10 minutes in the toner until it appear that all the toning was completed. The prints were collected and held in a tray which was being syphoned with a Kodak tray syphon for approximayely 1/2 hour. The prints were hardened in the following formula: Water that made a liter when combined with sodium sulphite 15grams, 40ml 28% acetic acid, 15 grams of potassium alum for 5 minutes with hand shuffling. The prints were washed in a large tray with the water being dumped and refilled while a Kodak tray syphon was running off the water line for an hour. Then the prints were then given five 20 minute cycles of soaking and shuffling dumping and refilling the trays with fresh water. The prints were then dried.

I am more than pleased with the toning results. I very much like it.

I have a few questions.

Having gone thru all the following is there any test of the final wash available?they certainly should have been hypro free prioir toning and no staining whatsover is evident so I am only asking about the final washes.

Is this thiorea formula for sulphide toning as good as the other types FOR PRINT LONGEVITY including hypo alum, and the rotten egg smell enhanced sulphide flake toning?

Are there any test available that can be fairly reasonably done by the darkroom worker to determine that the final print should be longlasting?

Thankful am I to you to take the time to read and respond to my questions.

 

[Ian Grant]

It appears you washed your prints very thoroughly so no need to worry about that.

Your question about whether the Thiourea toner is as a good as others for print longevity is valid, as the silver is now in a complexed as opposed to being the pure metal it's not going to be attacked by airbourne sulpides, or trace chemicals left in the paper from fixing.

However it's important to remember that the alternative suplide, & polysulpde toners work equally as well but can yield very different changes in image colour.

There's no chemical test to show print longevity, in the darkroom.

Ian

 

[Photo Engineer]

Claire;

Thiourea is also a fixing agent for silver halide. Therefore, I've always regarded the thiourea toning to be less desirable as it might remove some of the finer grains in the silver image rather than turn them into sulfided silver. Since I have always been somewhat dubious about this, I prefer the sodium sulfide toner.

If you notice no problem, then by all means ignore what I said and continue, as all else you did seems fine. The statement above is just an opinion on my part with no proof. Sometimes too much knowledge can be dangerous. In this case it may be making me overly cautious.

PE

 

[Claire Senft]

Thank you for your helpful responses There was a bit of print reduction from bleaching and redeveloping that enhanced my feelings about the prints by adding what I consider to be nice touch of print brilliance.. I am hopeful that there will be no further bleachng etc over the years.

 

[RalphLambrecht]

Claire

I only use direct sulphide toning, so, I can't help much, but the use of hypo eliminator concerns me. The use of hypo clearing agent or many other washing aid is a better choice.

The three essential elements for effective washing are the use of washing aid, water replenishment and temperature. Washing aids, also known as hypo-clearing agents, are marketed by Ilford, Kodak, Tetenal and others. These products help displace thiosulfate and improve washing efficiency. Washing aids are not to be confused with hypo eliminators, which are no longer recommended, because ironically, small residual amounts of thiosulfate actually provide some level of image protection. In addition, hypo eliminators contain oxidizing agents that may attack the image. There is little danger of over-washing FB prints without the use of hypo eliminators.

However, over-washing is a risk with some RC papers, and the use of washing aid is therefore discouraged for RC processing. Nevertheless, with FB prints, the use of a washing aid is highly recommended, because it conserves water, reduces the total processing time by about 50%, and it lowers residual thiosulfate levels below those of a plain wash. Its use increases washing efficiency in cold wash water and overcomes some of the wash retarding effects of hardener. Processing times vary by product, but all washing aids dramatically reduce the archival washing time, also limiting the potential loss of optical brighteners from the paper.

 

[Claire Senft]

Thank you Ralph. I am aware choice of hypo eliminator vs HCA etc. makes a
difference in possible damage to the paper structure vs having a small amount of residual and benefical fixer in the print. My own personal choice has been made due to my feeling that in testing for residual fixer it is difficult to be sure the ideal state has been reached, that the ideal state has been properly defned in the first place and that whatever test I make will be valid for the whole sheet of paper. On the other hand all the prints are drymounted on 4 ply board and kept in archival boxes with acid free intereleaving paper between sheets. So the prints are somewhat protected from enviromental attack and fairly well protected from physical damage..

I hope that I have made the right choice.

 

[gainer]

I have a feeling that residual fixer would have combined with the ferricyanide to do bad things, such as removing some of the image either evenly or unevenly before the toning took place, and will have no further effect on the silver sulfide image.

 

[RalphLambrecht]

Claire

To be clear, we don't want residual fixer in the print, but we are not worried about traces of it. There is no way to control the amount, but proper fixing, HCA, and proper washing combined with sulphide toning is all one needs to do prior to appropriate storage and display. Hypo eliminators may do more harm than good.

 

[gainer]

Perhaps I didn't word my post properly. I have no idea exactly how much residual fixer it would take to reduce the image contrast or density noticably, but if it had been in the print before toning that is how it would have showed up. It will not be there after the bleaching prior to toning because the combination of ferri and hypo is a reducer which washes out along with the silver it removes. That is why I believe that washing before bleaching before toning should be very thorough. The usual rule that a small amount of residual fix may be beneficial does not, IMHO, apply here. The chances of there being any after toning are practically nil, and any that is present before toning can only have bad effects.

 

[Jordan]

Hi Claire, I use the exact toning solution you describe (2 g thiourea plus 100 g sodium carbonate per litre) as a fogging re-developer in B&W reversal processing. I'm sure you know that you can control the image tone you get, to a certain extent, by changing the alkalinity of the toner. More base is said to produce a more chocolatey-brown (as opposed to orange) tone.

P.E.'s concerns about possible image reduction by thiourea are certainly something to take note of, but I think that the rate of the AgX -> Ag2S reaction (the one you want for toning) is likely to be hundreds or thousands of times faster than the rate of the "fixing" reaction at this pH.

 

[Photo Engineer]

Thiourea plus ferricyanide is equivalent to a one-shot color blix. It removes silver and silver halide.

Therefore, it is essential that these two ingredients never mix when toning.

In addition, thiourea is a fix, and therefore it can, under the right conditions, fix the bleached image as well as tone it.

PE

 

[Claire Senft]

Thank you one and all. You have been most helpful am I am sincerely most appreciative.