PDA

View Full Version : Iodine bleach formula.


Nabhar
16th April 2011, 11:42 AM
Reading my way through Tim Rudman's Toning Book (Selenium Toning section).
I would like to try my hand at 'Chinese' prints, making and using the given Iodine bleach formula. Although Tim mentions that Iodine tincture can be used, there only seems to be a mixing formula given for using Iodine Crystals....

Methylated Spirits....................100ml
Iodine Crystals
- as much as will dissolve...........(about 6-8g = 1tsp)
Dilute 1+10 for use.

....After searching FADU with the terms 'Chinese' and 'Iodine', I searched on flea-bay for the Iodine, and was confronted by a bewildering array of Iodine products, which have an equally bewildering array of additives in differing proportions. I am in doubt as to which of these might be suitable.
My question is.... ** where I can source the most suitable form of Iodine Crystals for this process, in the UK ? **
Also, if my search here at FADU was too shallow, could someone direct me to a previous post where this process has been discussed ?
Any tips on this technique from members who have previously tried this process would also be welcome. Or, direct links to any helpful sites that can offer more advice to me concerning this technique ?

Thanks
JP

Trevor Crone
16th April 2011, 02:23 PM
Iodine can be purchased from Silverprint (http://www.silverprint.co.uk/ProductByGroup.asp?PrGrp=49&sort_dir=0-0-0&sort_column=7-8-0&Start=50)

There is another formula known as 'Lugol's Stain', which I once used extensively for silver print bleaching. This bleach is excellent for reducing to paper base without staining.

Iodine (resublimed).......4g
potassium bromide........15g
water to make 1 litre.

Remove brown stain with 30% sodium thiosulphate solution - wash print well.

Nabhar
16th April 2011, 04:04 PM
Thanks Trevor,
I found the Silverprint product just after I posted, but still wasn't sure if this was the stuff I needed (dissolves in Meths). I'll take it from your direction that it is , thanks.

I'll also look for links to info on Lugol's Stain.
''excellent for reducing to paper base without staining.''
''Remove brown stain with 30% sodium thiosulphate solution''

I'm a little bit confused, does this mean it stains the tray(and surroundings) but can be wiped away with 30% sodium thiosulphate solution.

ps ...I am aiming to get close to the vivid orange colours indicated in the book. As you probably guessed, I'm very new to toning, so thanks for your understanding.

JP

Trevor Crone
16th April 2011, 05:21 PM
JP, yes, resublimed iodine is what you want. It is not very soluble in water but dissolves readily in a solution of potassium bromide or ethanol (methylated spirit).

When you apply the working solution of iodine/potassium bromide (Logol's stain/solution) to the silver print you get a brown iodine stain as it starts to bleach away the image. This can be easily removed with either a quick soak in 30% sodium thiosulphate for large areas or by blotting with the thiosulphate for a smaller area of bleaching. Once this is done there is no hint of stain.

Timrudman
21st April 2011, 08:49 AM
Thanks Trevor,
I found the Silverprint product just after I posted, but still wasn't sure if this was the stuff I needed (dissolves in Meths). I'll take it from your direction that it is , thanks.

I'll also look for links to info on Lugol's Stain.
''excellent for reducing to paper base without staining.''
''Remove brown stain with 30% sodium thiosulphate solution''

I'm a little bit confused, does this mean it stains the tray(and surroundings) but can be wiped away with 30% sodium thiosulphate solution.

ps ...I am aiming to get close to the vivid orange colours indicated in the book. As you probably guessed, I'm very new to toning, so thanks for your understanding.

JP

Just saw this JP.
Just be aware that if you go for that complete vivid orange look by removing every trace of silver the orange print will also look extremely flat. If you 'peel back' the black silver slowly using iodine, the orange starts to glow through the silver image which initially retains it's contrast and texture with a lovely luminosity.
Like most things, it's a matter of taste as to how far you take it.

Nabhar
5th May 2011, 06:26 PM
I've just been on to Silverprint, and have ordered the resublimed Iodine. I have also ordered 100g Potassium Bromide, and will have a go at making my own Lugol's Stain (thanks Trevor).
I'll pay close attention to the bleach-back procedure alluded to by Tim, as one of the subjects matter that I have in mind to cover in mid-July will be more suited to this more delicate balance.
Hopefully I will get something half decent out of it all.....will post for criticism if and when I do.

Having recently gone through my first two toning sessions (using Sepia, Selenium, and Gold toners), I've found that (while constrained to a tight budget) my 1 litre bottles of working solutions are only marginally covering my 12x16 sheets in the trays, and require constant agitation to keep the paper uniformly covered. :(
Looks like an upgrade to 2 litre bottles is required (for the larger copies anyway).

Thanks again for the insights, Trevor and Tim. :cool:

JP