Lith: Bleach & Tone vs. bleach & redevelop formulas

[M Carter]

I'm about to play with some more extensive lith printing, and I want to experiment with bleach & tone and bleach & redevelop. Thinking of making a pile of test prints and playing with the processes. I don't have a specific need for a specific print, just want to see the effects on available papers.

Reading Tim Rudman's book, he mentions "weak ferri alone" (no bromide) for light bleaching, and states if it's not what you want post-washdown, you can bleach more or redevelop.

He also mentions ferri/potassium bromide bleach for redeveloping and for light bleaching before toning. I have only used bleach for spot-bleaching. So...

1) I've always assumed bleach needs potassium bromide for redevelopment to be possible. Is this true?

2) What happens with bleaching for redevelopment or light bleaching for toning with just ferri alone?

3) Lots of conflicting recipes for ferri/bromide bleach - I've read bromide affects the speed of the bleach, and seen 1 liter recipes ranging from 60g ferri + 4g bromide, 50+10, and on up. Any guidelines?

4) I've got plenty of ferri but no pot. bromide - if I'm too antsy to wait for a delivery, I understand regular salt can replace the bromide - is this correct and are there any guidelines?

As usual, thanks!

 

[Rudeofus]

1) I've always assumed bleach needs potassium bromide for redevelopment to be possible. Is this true?

Potassium Ferricyanide will bleach your film alone, albeit slowly and maybe incomplete. For brightening your print this may be all you need.

2) What happens with bleaching for redevelopment or light bleaching for toning with just ferri alone?

I would assume Silver Oxide will form, or Silver Hydroxide.

4) I've got plenty of ferri but no pot. bromide - if I'm too antsy to wait for a delivery, I understand regular salt can replace the bromide - is this correct and are there any guidelines?

Chloride in high concentrations will dissolve Silver ions, which means you can bleach but not redevelop/tone. Likewise I'm not sure whether you can redevelop/tone Silver Oxide/Hydroxide. I would suggest you ask your local pharmacy about Potassium Bromide, they might just have it, even if their prices may be outrageous and they make you sign a phone book sized stack of paperwork.

 

[Rich Ullsmith]

1) Yes, you need a bromide ion to rehalogenate the the image. Or some other halogen.

2) If you bleach with ferri alone, this is a one way street. Until you get a feel for your paper and how it responds to the bleach, I would stick to the KBr/ferri so you can bring it back if you accidently go too far. If you aren't worried about destroying the print and are just experimenting to learn, have fun. P.s. you need to refix after bleaching if you use KBr/ferri. No refix necessary if just using ferri.

3) Make two stock solutions: 100g KBr/1000ml, and 100g ferri/1000ml. For starters, 1+1+20 water. You can always add more if it too weak for your paper. RC papers bleach pretty quick.

4) NaCl is used in some bleaches, but I think the problem here is not the chloride ion but the sodium cation. Maybe if you had potassium chloride, I don't know.

Tim has a good formulary in his books. The KBr/ferri and the copper chloride are good for starters.

 

[M Carter]

Thanks guys - yes, I've used ferri followed by fix for spot bleaching, just trying to suss out what might work with Lith. And yep, this will be playing around to some extent, messing with different exposures, seeing how post-dev processes and bleach work together.

 

[Simonh82]

Potassium chloride is often sold as a table salt substitute. In the UK it is called Low Salt. I don't know what other additives there may be in there though.

 

[Rudeofus]

Potassium chloride is often sold as a table salt substitute. In the UK it is called Low Salt. I don't know what other additives there may be in there though.

Trust me, it's not the Sodium that makes a Ferricyanide/NaCl rehal bleach unviable. It's the fact, that high amounts of Chloride dissolve Silver ions, as exemplified by Microdol.

 

[pdeeh]

I have some rehal bleach solution that I made ages ago using Copper sulfate and Sodium chloride (what I presume is a Copper chloride bleach) that seems to work OK. Can't remember where I got the formula or what the formula was but I think it was on APUG somewhere.

Why would that work but a ferri/salt bleach not work?

 

[Rudeofus]

This page claims that you can dissolve fractions of a gram of Silver Chloride per liter of Sodium Chloride solution, strongly dependent on concentration of NaCl. If your bleach uses little Sodium Chloride, and highlights are not that important to you, you may not even notice a difference. The solvent effect is also much more pronounced if you use Silver Chloride paper instead of Silver Bromide paper or Silver Bromide Iodide based film. YMMV.

 

[pdeeh]

That's interesting, thanks.

Having had a sniff around APUG, I think the basic formula I used was was 100g Copper sulfate + 100g Sodium chloride in 1000ml water. Don't know where that concentration of salt fits on a "high-low" scale.

I think I tried it out of ignorance rather than design, and I never did more than try it with a few scrap test prints, but it certainly bleaches out an image, and the image can then be redeveloped. I didn't carry out any more methodical tests or inspect the results too closely, so I can't comment on how it affected the image subtleties.

 

[paul_c5x4]

From The Master Photographer's Lith Printing Course:

Copper Sulphate bleach

Copper Sulphate 50g
Conc. Sulphuric Acid 6.5ml
Sodium Chloride 50g
Water to make 1 litre

Dilute 1+9 for better control of the bleaching process.

As one recent example, feel free to have a look at my (there was a url link here which no longer exists) print which was bleached in the above solution and redeveloped in D-85.

 

[Rudeofus]

Having had a sniff around APUG, I think the basic formula I used was was 100g Copper sulfate + 100g Sodium chloride in 1000ml water. Don't know where that concentration of salt fits on a "high-low" scale.

Further down the table you have values for 76.7 and 115 g/l Sodium Chloride, and a simple extrapolation would suggest that you can dissolve between 25 and 30 mg Silver Chloride per liter of 100 g/l Sodium Chloride solution.

That's not a whole lot, but take a look at the highlights in Paul's Buick image ... beautiful print, though.

 

[M Carter]

I have the Master Photogs Lith book, great resource. The recipes for Ferri/Bromide I'm finding have very different ratios though. I may mess with the sulfuric acid recipe, though part of me doesn't want that stuff in the house unless a drain is stopped up!

I also have a mess of Bromoil bleach chemistry since I've been working with Bromoil. don't know if that redevelops though. I don't think I'll ever have the brain-space to grasp the chemistry, but I do have a good notebook going with recipes, tests and results. Thus my curiosity regarding straight ferri vs. ferri-bromide (per the mention in the "Master Lith" book).

Rudman does claim the ferri-only bleach can be redeveloped and that he often likes the effect. He's very clear on that, that a no-bromide bleach will redevelop. Yet posters here say no.

I've always though of straight ferri as a spot-bleach or overall lightener, I guess I'll have to test the redev properties.

 

[paul_c5x4]

There are other recipes for copper bleach - If you have Tim's book on toning, you'll find three or four others. Bichromate bleaches also produce interesting colours, but are worse than sulphuric acid.

If you don't like the idea of concentrated sulphuric acid (98%), battery acid is usually around 30% which can be used at a rate of 20ml per litre.

 

[Rudeofus]

I have the Master Photogs Lith book, great resource. The recipes for Ferri/Bromide I'm finding have very different ratios though. I may mess with the sulfuric acid recipe, though part of me doesn't want that stuff in the house unless a drain is stopped up!

The phrase you are looking for is "flat optimum", in other words, Ferricyanide is a very powerful oxidizer, Bromide makes it even more powerful and efficient. By adjusting compound amounts you strike a balance between bleach capacity, bleaching speed and cost. I have read that Ferricyanide in aqueous solution will go bad after some time, the less Silver you need to bleach in one session, the more dilute your bleach can be.

Rudman does claim the ferri-only bleach can be redeveloped and that he often likes the effect. He's very clear on that, that a no-bromide bleach will redevelop. Yet posters here say no.

Does it fully redevelop, or only some parts of it? Note, that Silver Oxide is not all that insoluble, a prolonged washing step might already reduce some highlights. BTW what does Rudman mean with "he often likes the effect"? Is there indeed some effect that changes the appearance of the print?

 

[M Carter]

BTW what does Rudman mean with "he often likes the effect"? Is there indeed some effect that changes the appearance of the print?

PG 106 - paraphrasing with the book in front of me:

"the soft touch" - Subtle and lovely effects (photo example is very high-key) with straight ferri alone.

Gentle colors, ice-cold highlights, just 1/4 stop overexposure - or get stronger effects with more exposure and longer bleaching.

5-10 ml of 10% stock ferri solution into one liter water, bleaching between 15-25 minutes, gentle agitation.

If on washing or drying the effect isn't as desired, bleach some more or redevelop and rebleach. The double cycle can give nice effects.

VERY thorough wash (to keep fix and remaining bleach from activating together), followed by fixing (may affect colors, use a gentle fix - dilute Sodium thiosulphate).
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