Iodine bleaching - any experiences to share?

M Carter

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Recently discovered iodine/thio/alcohol bleach, for spot bleaching dry prints. As the kids say, "OMG!" Where have you been all my life. Amazing tool, from subtle creative fixes to retouch/repair. Wonderful addition to the toolkit.

Questions - Tim Rudmans' recipe uses iodine crystals and methyl alcohol - neither are common to obtain but found via mail order. Can I just mix tincture of iodine with thio for the same effect? (Don't know the purpose of the thio, but it does convert the iodine to clear liquid, which makes working much easier).

In this process, you wipe the working area with methyl - will another alcohol work? Methyl I could only find in small quantities by mail, and was expensive. 99% iso? Denatured? Everclear? Is there something special about the methyl? (And do you like my haiku?)

This brings me to "china" bleaching - as my stock of Ektalure decreases, I'd love to find a way to those burning oranges (see my avatar) with some lith prints. China bleaching uses a fully selenium toned print, which is then bleached in an iodine crystals/methyl bleach. To do a 16x20, this would take a lot of crystals. Would drug-store tincture work for this process?

I know, I know - "test it yourself", but if anyone's already gone through such testing, would love a head start!
 

Gerald C Koch

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Yes you can use commonly available tincture of iodine. For small spots I apply it with a wooden toothpick. For very small spots the toothpick can be sharpened to give a finer point. I do however refix the print to be on the safe side.. No need for the alcohol in this case.
 

Ian Grant

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I used an Iodine bleach extensively:

Ilford IR-4 Iodine Reducer

Potassium Iodide 16gms
Iodine 4gms
Water to make 1 litre

Dilute 1+19 for use

Often I needed to cut away a part of the image and unlike a Ferricyanide/Bromide bleach this works far more effectively. Iodine bleaches can leave a yellow stain but it's easy to remove. Wash then re-fix, if any staining is left wash and swab the area with some developer and the stain goes completely, then re-waskh.

Ian
 
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M Carter

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I guess alcohol could be used to cut the bleach for more control? With Rudmans' process, you put some alcohol on a cotton ball and wipe away the bleach as you work, so you can control the depth of bleaching yet keep the print surface dry. I've had great success with a #000 brush, from killing dark spots (then spot-tone the white spot) or just enhancing details.

I have a fair amount of crystals but I'm interested in doing the post-selenium "china" bleaching, which would take a lot of iodine for a large print.
 
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M Carter

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Ian, in this recipe, is the iodine 4gm of iodine crystals? Or crystals dissolved in alcohol? The bleaches I've used with crystals start with x-grams of crystals and enough alcohol to dissolve them.
 

Rudolf Karachun

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The drug store iodine solution can be used alone for spot bleaching. On Amazon the colorless iodine solution can be found. It used by people to cure some skin problems but for the photographic purpose working the same as colored. One book state that the water can be added to the drug store solution to make it less aggressive. I didn’t try this. Another book state that the iodine continue bleaching process even after drying, so be careful. Chemically speaking when silver meet iodine it creates a silver iodide. Silver iodide previously or maybe today to, used in B&W film and paper manufacturing together with silver bromide and silver chloride. In Soviet Union used to be a photographic paper called “IODOBROM” for example. Same as the silver chloride and silver bromide the silver iodide can be dissolved in fixer and removed from the paper. So after bleaching the fixing required.
 
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M Carter

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Yep, I've always re-fixed after iodine - supposedly just washing with water will create stains.

I guess I'll test some scraps with drugstore iodine for the china-style bleaching. I don't always want flaming reds, but I've gotten spoiled by ektalure and lith developer.
 

Ian Grant

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M Carter said:
Ian, in this recipe, is the iodine 4gm of iodine crystals? Or crystals dissolved in alcohol? The bleaches I've used with crystals start with x-grams of crystals and enough alcohol to dissolve them.
Click to expand...

Crystals, however you could add it in any form as long as you calculate the equivalent quantity.

Ian
 

Gerald C Koch

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If using iodine crystals there is no need for the alcohol. Iodine will dissolve in potassium iodide solutions. This is a problem when you have photographers with no knowledge of chemistry devising solutions.

When using decolorized (white) iodine you also need to refix as the iodine is decolorized with sodium thiosulfate.
 
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M Carter

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Gerald C Koch said:
If using iodine crystals there is no need for the alcohol. Iodine will dissolve in potassium iodide solutions. This is a problem when you have photographers with no knowledge of chemistry devising solutions.
Click to expand...

Ummm... the recipe was from Tim Rudman for china bleaching - the other use was wiping prints when spot bleaching dry.

Methylated spirits 100.0mls
Iodine crystals as much as will dissolve
Dilute 1+10 for use.
Click to expand...
 

Gerald C Koch

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Patrick Robert James

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I use it straight out of the bottle from the pharmacy. Usually I use a brush with the print out of the fix. Wipe the print, apply the Iodine, easy does it... When the spot is bleached I put the print back in the fix and continue on. Works fine.

I prefer to fix the neg itself if the neg is large enough. I spot it with a careful hand and a Sakura pigment ink pen on the non emulsion side. It works fine for 4x5 and 120 usually, but 35mm creates a spot that is too large so I use Iodine on the print in that case.
 
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M Carter

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I'm really fond of the dry-bleaching - iodine, thio, alcohol. You can do things like brighten individual hairs that would be impossible with wet bleaching. (The bleach itself is "wet" but you use it on a dry print, and it evaporates very quickly. You wipe the spot with alcohol and work it until happy). Great for removing dark spots that are too small to fix on the neg, too. You do need to re-fix after.

I have times in lith printing that I'll get one oddball black grain in a smooth sky (not on the neg, seems to happen with my old stash of MC-110 a lot), it's a life saver for that as well.
 

Rudeofus

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It will likely work, but it will create Silver Iodide, which is difficult to develop and difficult to fix.
 

Raghu Kuvempunagar

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Rudeofus said:
It will likely work, but it will create Silver Iodide, which is difficult to develop and difficult to fix.
Click to expand...

I had reversal processing in mind. That AgI is difficult to develop could be great for reversal processing. But if it also difficult to fix then probably not worth the trouble.
 

Rudeofus

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If you look at solubility product of silver halides: pKsp of AgCl, AgBr and AgI is about 10-10, 10-13 and 10-17. Stability constant of higher order silver thiosulfates is about 10-13.

If you develop Silver Iodide, you release lots of iodide, which then acts as a powerful restrainer. If you use this bleach for reversal processing, you may end up with some unwanted base density.
 

KPA40

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Raghu Kuvempunagar said:
Can this bleach be used in B&W reversal for bleaching the silver image after first development?
Click to expand...

Reading your question i remembered a reversal process based on iodine before. I found it in this german book from 1965 (?) of Dr. Edwin Mutter: "Kompendium der Photographie, II. Band, Die Negativ-, Diapositiv- und Umkehrverfahren", p. 259-260. Don't know if there exists an english version. Dr. Mutter refers in it to an old technique by Brooks and Caroll from 1883. I find this interesting as it avoids the need for the toxic dichromate bleach or the unstable permanganate bleach. I have no idea if this procedure can even work with modern films, but I think i should give it a try occasionally.



Translation:
1. Negative development
2. Bleaching of the silver image in an alcoholic iodine solution or iodine potassium bromide solution. The image silver of the negative is thereby converted into silver iodide and is no longer capable of development.
The remaining silver bromide of the emulsion remains unchanged. A solution of iodine in potassium iodide is unsuitable as it also converts silver bromide of the emulsion into silver iodide.
3. Second diffuse exposure
4. Positive development (it develops the silver bromide of the emulsion, but not the silver iodide)
5. Fixation in a normal acid fixer bath (the silver iodide is removed from the layer, a positive silver image remains)
6. Wash
The graphic should be self-explanatory.

Regards Olaf
 

Raghu Kuvempunagar

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Thanks Olaf for sharing this! I was interested in exactly this and for the same reason - to avoid dichromate and sulphuric acid in reversal. I have used Copper Sulphate + Sodium Chloride bleach and got good results, but it requires Ammonia. Wanted to avoid Ammonia too and was interested in Iodine/Iodide bleach.
 
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