Bleaching - Warming up effect

[delphine]

I am trying to work with a bleach back process before redevelopment and or selenium toning.

However, I am experiencing an unwanted warm up in the hightlight tones. I managed to cool tone down the warming up by redeveloping briefly prior to selenium toning.
Playing around, I had a drastic warm up of the print after I bleached & redeveloped twice... this said, I had some blue blacks shadows then.

Why did the bleaching warm up the print?
How can I avoid this effect. I want to keep the print cold.

Data:
Print dev : Eukobrom
Bleach: home brew (10gr Potassium Ferricyanide +10 gr Potassium bromide to make 100ml stock used at 1+49)
Print redev : Ilford cooltone
Selenium tone: KRST

Thank you all

Dee

 

[snallan]

Hi Dee, very dilute ferricyanide on its own can be used to warm-up prints, though normally using dilutions in the 1:100 to 1:200 range, for 30 minutes or so. So I wonder if this might be occurring as a side effect of your bleaching.

 

[Doremus Scudder]

Potassium ferricyanide and KBr is a rehologenating bleach. This means you are "manufacturing" silver bromide. The composition and grain size of the AgBr is going to be different than that of the original silver halide(s) in the paper you are using. It will develop to a different tone and tone differently in selenium toner. There is really no way I know to alter the change in tone resulting from this.

I bleach occasionally and tone in very dilute toner to minimize the effect, which I find unpleasant. Redeveloping can only make the tone change more pronounced.

If anyone does know a way to more successfully deal with this tone change. I'd be very interested in hearing it!

Best,

Doremus Scudder

www.DoremusScudder.com

 

[keithwms]

Try farmer's reducer. And wash thoroughly.

(N.b. I am not familiar with the paper you mention)

 

[Rich Ullsmith]

Hi Delphine. Not sure what you are trying to accomplish with the bleaching and redeveloping.

I assume your paper is silver bromide (vice silver chloride or chlorobromide), fairly cold, and you are using a cold tone developer. Bleaching and redeveloping, particularly in the same type developer, is going to accomplish little beyond losing a little density in the highs, resulting in warmer highs. The toning characteristics will change in these areas also; not certain, but I believe this is due to residual rehalogenated silver that was not completely redeveloped.

It's fun to play with, but the bleach/redev thing really isn't the way to cool a print off, if that is what you are after.

 

[pentaxuser]

It's not an answer to your problem, in fact probably quite the reverse but if you have Tim Rudman's book have a look at page 115 where he speaks of the warmtone effect and gives an example of a before and after print. It is quite amazing, ressembling almost a lith print. So it appears that very dilute ferri has this property which in this case is not what you want but indicates how strong an effect it has.

However the whole chapter is devoted to bleaching including a bleach/ redevelop cycle where he speaks of the ability to modify the image, in warmer or colder tones depending on the developer.

I've said this twice now in almost as many days but at the risk of sounding like a T Rudman salesman, I'd get the book if I were you. It is a real gem.

The book is The Photgrapher's Master Printing Course.

pentaxuser

 

[delphine]

Hi Pentaxer,

I have Tim's toning book not the master printing course. The toning book is a real gem and I have re-read several times the same pages about bleaching. I found no direct reference to the warming effect. There are many bleach recipes though.

Since you have the master printing course (which I am adding to my order list), what would your advice be?
Should I be using a different bleach then? Or could I tame the warm effect by adding some benzotriazole to the bleach?

Many thanks

Dee

 

[pentaxuser]

Sorry if it sounded as if I was a bleaching expert. I am not. In fact not even a user of bleaching as yet. Just someone who is finding out how many pearls of wisdom there is in Tim's book. My interpretation of Tim's comments on bleach/redevelop is that the key is using the right coldtone developer after bleaching. It would seem that for the bleach/redevelop cycle you do not use very dilute bleach for a very long time which is what produces the warmtone.

Benzotriazole, I think, should be added to the developer. My experience of getting very coldtones was Ilford Cooltone paper in Cooltone developer which is still available. Whether adding benzotriazole to Cooltone developer gives even colder tones, is something I don't know but I can say that Cooltone paper in Cooltone developer is noticeably colder than anything else I have ever used.

For what it is worth I added benzotriazole recently to Ilford WT developer to cure fogging in some aged Agfa Premium paper and it certainly seemed to reduce the warmtone effect of the developer but it has to be remembered that Agfa Premium is a neutral/ cold toned paper anyway and it is difficult to isolate the benzotriazole effect from the Agfa paper effect.

I suspect that experimentation is needed. Best of luck

pentaxuser

 

[kevs]

Hi Dee,

You didn't mention whether you were fixing your prints after bleaching them. As Doremus mentioned, your bleach is re-converting the metallic silver into silver halide, a step normally undertaken before sepia toning a print. If you now re-fix the print (fresh fixer) without re-developing it, after a brief wash, the warmer toned highlight areas (ie the re-halogenised silver) will dissolve to leave the unaffected areas in the original tone.

Bleaching-back is a two-step use of Farmer's Reducer, a very useful technique for rescuing over-exposed prints and adding a little contrast to the print. However, it's irreversible - you can't re-develop what ain't there any more! After a brief wash (10 mins - don't worry unduly because there's thiosulphate in the selenium toner) you can selenium tone as normal.

Also, remember that papers change tone as they dry - FB papers in particular will change tone as they dry. You didn't mention your paper type - perhaps someone will have tried this with your paper.