Diffusion Transfer Printing ("Polaroid" peel-apart) recipes

[alecrmyers]

I would love to try it if youre still looking for volunteers

Send me your address and I’ll send some materials.

 

[OrientPoint]

@alecrmyers What is the role of the trace amount Sodium borohydride in your paper recipe?

 

[Ethan Brossard]

Those are some interesting ideas. There’s actually more than enough silver in a regular film to give a black print - but as you’ve noticed, it’s not always easy to get it to the right place. Looking forward to hearing about your results!

Thinking about how film development works versus paper development, film is immersed in the developer solution for far longer. I wonder if the gelatin emulsion hardness and possibly anti scratch layers play a roll in the reduced diffusion of silver across the reagent. a more alkaline reagent will cause the gelatin to swell more, and possibly allow for greater diffusion of silver across the reagent. have you experimented with increasing the concentration of sodium hydroxide in your developer/reagent base?

 

[alecrmyers]

@alecrmyers What is the role of the trace amount Sodium borohydride in your paper recipe?

Sodium borohydride is a standard laboratory reducing agent. In this case it immediately reduces palladium chloride to elemental palladium. It's not persistent as it decays on contact with water releasing hydrogen (it has been explored as a hydrogen storage medium for vehicle fuel).

 

[alecrmyers]

Working in the lab (basement) I was able to synthesize some di(methoxyethyl)hydroxylamine - DMEHA - which was reported in this post in this thread as the active developer in the Polaroid coaterless products. I've been trying it out today and the good news is that it doesn't appear to have any advantages over DEHA other than that it doesn't smell bad. In the picture below the left side is developed with DMEHA and the right side with DEHA and there's not a significant difference. (I am still working on the streaking, obviously.) In a way that's good news because DEHA you can buy, and DMEHA you can't.

 

[MsErinD]

Send me your address and I’ll send some materials.

i cant private message you since i am new to the forum. my email is *******

{Moderator's note - please do not post private emails in public posts - the scammers are out there.
@alecrmyers can pm you, and you can respond in that Conversation}

 

[OrientPoint]

Sodium borohydride is a standard laboratory reducing agent. In this case it immediately reduces palladium chloride to elemental palladium. It's not persistent as it decays on contact with water releasing hydrogen (it has been explored as a hydrogen storage medium for vehicle fuel).

I see. So it's there to provide elemental palladium for nucleation sites. The precise amount of sodium borohydride doesn't matter though? You mention using trace amounts in your paper. If two pinches are used where one would suffice, the excess will just decay with no other effect?

 

[alecrmyers]

If two pinches are used where one would suffice, the excess will just decay with no other effect?

As far as I know. However - a “pinch” is too much. For 10ml of coating, which is enough for 20 8.5x11 sheets, I use sodium borohydride enough to cover about a quarter of a match head. The crystals are about the same size as kitchen granulated sugar (sucrose) crystals, and I add about five or six of them. Perhaps even less of the material is actually required. There is very very little palladium there to be reduced, after all.

 

[OrientPoint]

My "pinch" is better termed a micro-pinch, but not as small as you describe. It's good to know that your trace usage is that small. As you note, there's only a minute quantity of Palladium present in a few ml of 0.1% solution. I probably should not be too worried about having too little reduction agent.

 

[alecrmyers]

A rough analysis suggests the stoichiometric quantity of sodium borohydride needed to reduce 0.5ml of 0.1% palladiium chloride is about 50μg. you might reasonably want to use a small multiple of that to ensure rapid completion. For comparison a single crystal of granulated sugar weighs about 1mg (1000μg) according to online sources (although figures for that seem to vary wildly. I will set some small children to counting the number of borohydride crystals in 100mg and report back.)

(edited again because I can't seem to divide 4 by 2 and get the right answer...)

 

[richyd]

This is the last of the exposures. Very pleasing as before. The image is bluer in tone than the previous one which had a yellow tint. I don't know why the difference with the same materials - exposure? I managed to get the mechanical part of processing sorted now with less mess. I note that the developer supplied is labelled 148 is that much different to 143?

I still have a lot of developer left so will try to do some coating of receiver paper. It's difficult in the UK to get chemicals. I think I have found a paper type and a source for the chems apart from palladium chloride, at least in small quantities. I do have a fair amount gold chloride intended for use in toners, would that do instead of palladium? I guess the tone would be different. I have found two potential sources of silica suspension, one offers .09 micron and the other .06 micron, would either do?

I have a few sheets of Ektascan 8x10 x-ray film (single sided not made anymore) I could first try, would love to make some 8x10 prints. Again UK sources of x-ray film are few and expensive but I will see if a cousin in Netherlands can obtain for me from a German supplier.

 

[alecrmyers]

I expect a chloride salt of gold to work very well indeed; it will likely give a different tone (or may not) but not because gold is a different colour to palladium, obviously.

developers 148 and 143 are different, yes, but similar. I'd have to check my records to see what the differences are.

What are your sources for silica suspensions? I would be interested to see if there's a consistent tonal difference between the two particle sizes.

It's not at all important to use x-ray film specifically. It's merely the cheapest emulsion available by a long way, and happily is orthochromatic so easy to use. There's nothing special about it from the point of view of being for 'x-rays'. In any event Fuji HR-U is easily available for international delivery on eBay.

 

[alecrmyers]

A rough analysis suggests the stoichiometric quantity of sodium borohydride needed to reduce 0.5ml of 0.1% palladiium chloride is about 50μg. you might reasonably want to use a small multiple of that to ensure rapid completion. For comparison a single crystal of granulated sugar weighs about 1mg (1000μg) according to online sources (although figures for that seem to vary wildly. I will set some small children to counting the number of borohydride crystals in 100mg and report back.)

I weighed out 25mg of sodium borohydride and counted 38 crystals of various sizes. That suggests that a single crystal is tens of times more than is needed to reduce all the palladium present in 0.5g of 0.1% palladium chloride.

 

[OrientPoint]

I weighed out 25mg of sodium borohydride and counted 38 crystals of various sizes. That suggests that a single crystal is tens of times more than is needed to reduce all the palladium present in 0.5g of 0.1% palladium chloride.

Thank you. That's really helpful.

 

[Ethan Brossard]

update on my idea for adding silver to the reagent. The silver nitrate (somewhat expectedly) reduces immediately when added to the reagent, so this will not work. Would you mind sharing what your current solution is? One idea which a friend of mine had was to research what the chemical reversal bath in E-6 is, and see if that could be applied here, however my reading on that indicates it needs to be in a neutral ph solution to work, so would be incompatible I think.

Further thoughts on producing better reversals from film negatives:

perhaps adding a restrainer to the reagent, like benzotriazole, might reduce the silver which is developed in the film, and increase how much gets transferred to the receiver paper?

 

[richyd]

What are your sources for silica suspensions? I would be interested to see if there's a consistent tonal difference between the two particle sizes.

I came across these two sites after a quick search but don't know if they will supply to individuals. They are industrial machine polishing suppliers.

SILCO colloidal silica suspension, high concentration - Metprep

metprep.co.uk

Colloidal Silica & Alumina Polishing Suspensions - Kemet

www.kemet.co.uk

Oh, I have just done a search on ebay and found a few listings for silica powder for use as a filler in resins. Only one gives a particle size and that is .012 micron. I guess something like that could be used, though not sure of how much. More reasonble to buy.

I was after getting some more x-ray film anyway, I have used it for other alternative processes. Yes, cheap and ortho are advantageous but I also have a pack of 8x10 Ilford ortho film.

 

[alecrmyers]

perhaps adding a restrainer to the reagent, like benzotriazole, might reduce the silver which is developed in the film, and increase how much gets transferred to the receiver paper?

I think you need to try out these ideas and say which ones work. Ideas are cheap - working ideas are very rare and usually result in a patent for the lucky discoverer.

 

[alecrmyers]

Oh, I have just done a search on ebay and found a few listings for silica powder for use as a filler in resins. Only one gives a particle size and that is .012 micron. I guess something like that could be used, though not sure of how much. More reasonble to buy.

Powdered amorphous fumed silica for resin packing is widely available here but I had no success generating an aqueous suspension at anything close to the required solid content (30% solids is a typical value for liquid suspensions) without it gelling. YMMV.. additionally when you realize that a litre volume of silica powder weighs only a few grams and would produce only 10’s of ml of suspension at a decent solid content - it doesn‘t look so cheap.

 

[alecrmyers]

This is an extract from Land's own chapter in Neblette's Handbook of Photography and Reprography (7th ed.) published 1977 that will be of interest to anyone working in this process.