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

I don't have most of those chemicals, but regardless I'm keen for it. It's something I've wondered for a long time but without any sort of guide on where to start I never took the plunge.

Re: Howard Rogers. Yeah it's no wonder that Polaroids are said to be the most chemically complex invention the human race has ever created!

Of course, a few people sharing attempts and breakthroughs will almost certainly never get to the point of a perfect colour image etc, I'm sure a good b&W transfer with good contrast that's readily repeatable would be achievable.
I mean look what you've been able to do single handedly!

Where did you get the idea to split up the positive coating up into seperate phases before mixing? Is there a specific reason for it?

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BurntOutElectronics said:

Where did you get the idea to split up the positive coating up into seperate phases before mixing? Is there a specific reason for it?

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Trivial high-school chemistry is that zinc sulphide is insoluble in water - so mixing solutions of zinc nitrate and sodium sulphide generates a precipitate. However we want a colloidal suspension of nanometer sized crystals that stay dispersed long enough to mix with gelatin and be plated. In plain water, zinc sulphide tends to flocculate and sink to the bottom of the beaker in lumps. Various research papers show the use of poly(vinylpyrollidone) to stabilize metal particles in colloids, so I thought it worth a try. A lot of trial and error of different concentrations was involved; I have stacks and stacks of test exposures that didn't work.

As an alternative to zinc sulphide, I described above how you can make and use colloidal palladium, or else generate zinc sulphide from zinc sulphate and sodium sulphide. I didn't find a good source for zinc nitrate other than a chemistry supplier, but zinc sulphate shows on Amazon. I also spent some time trying to use zinc oxide powder (from a pharmacy); that would need titrating with an acid (sulphuric or nitric - wasn't sure about hydrochloric because of the inhibiting effects of the chloride ions) so there's plenty of experimenting to do. I also tried cadmium nitrate: it works, but cadmium sulphide is bright yellow which is disadvantageous on the white receiver paper. Lead ions (from e.g. lead acetate) work too, allegedly, but lead sulphide is black and forms an amorphous mass in solution; the opposite of a finely dispersed colloid. So there are lots of options to play with. i found one that works for me, but other people may have different preferences.

Interesting your note about presoaking the receiving paper before coating the paper with the two part solution.
That's probably a better way going forward just for consistency.
I really wonder what Polaroid used in their receiver paper, because afaik it never went bad and just looked like a thin clear glossy coating. The only thing that fails is the chemical pods after all these years and fogging of the negative material.

I'd like to know more about the purpose of the zinc, it seems like a rather fundamental part of the process. Is it some preferential reaction where the unexposed silver is exchanged for the zinc?

1phenyl-5-mercapto(1h)tetrazole - how hard to get is this?
I'll have to put together a shopping list tonight of everything you've said.
I've got heaps of 40mm wide ortho paper to use. Not wide, but good to give it some use.

The zinc itself isn't important - see my previous message. For information about the chemistry of DTP, I'd refer to the book Photographic Silver Halide Diffusion Processes (André Rott, Edith Weyde) from 1972.

The 1P5MT is not critical to the process. Try small quantities of cysteine as a toner without the 1P5MT.

BurntOutElectronics said:

I'll have to put together a shopping list tonight of everything you've said.

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Australian suppliers that I use:


Some "restricted" chemicals are available for purchase by individuals after you submit the "I am not a criminal" form to the supplier.

I prepared 16 sheets of 5.5" x 4.25" receiver paper from 11x8.5 "waterproof paper" HIGHH IMAGE (sic) brand (Amazon), coated with the receiver gelatin emulsion recipe 80 described in the first post. I used a 100µ wire-style coating bar. The paper was hung to dry vertically in ambient air.

I exposed 16 sheets of Ilford RC MG Deluxe at approximately ASA 6 (f/4.7, 8 second exposure time)

I made up a base as follows:

1000g 2%CMC
20g sodium hydroxide
20g sodium sulphite
16.7g sodium thiosulphate

and prepared in turn 4 developer solutions each of 30g of this base, adding to each 0.5g hydroqinone and 0.1g metol. Respectively to the second third and fourth preparation I added 3, 6 and 9 drops of a 1% solution of 1P5MT in ethanol. Each drop has a weight of 0.02g.

Then with each developer I developed one exposure, added 5 drops (0.05g per drop) of 10% cysteine HCl (in water), remixed, developed a second exposure, added a further five drops, mixed, developed a third exposure, then added a final five drops, mixed, and developed a fourth exposure.

Each development was achieved with approximately 1.5ml of developer spread between negative paper and receiver sheet using approximately 20mm wide 3mil (0.076mm) plastic film strips each side as the thickness guides.

Contact time was 60 seconds. Negative and receiver were separated under cool running water and the positive sheet was washed for 10-20 seconds under running water to remove any residual film of developer, then dried.

The results form a grid illustrating the response to increasing levels of cysteine HCl in the developer (moving the right) and levels of 1P5MT (moving down).



It's not very clear from this image (photograph of photographs etc.) but the best tonality and density appears in the second column from the left, around the second or third row. (Clearly this is a subjective opinion, but that suits my eyes best.) If you can't source 1P5MT, the results without it (top row) are quite acceptable.

For reference, the developer used in the second column third row has the following ingredients (if I've done my maths right):

29.4g water
0.6g CMC
0.6g sodium hydroxide
0.6g sodium sulphite
0.5g sodium thiosulphate
0.5g hydroquinone
0.1g metol
25mg Cysteine HCl
0.6mg 1P5MT
60mg ethanol as solvent for 1P5MT

As a practical matter I'd scale this up by at least two or three times to make mixing more practical. Also note this developer (like all the others I've described) browns rapidly while exposed to air, so if you want to keep if for more than few minutes before you use it and dispose of the remainder, I suggest pouring it into a syringe as I described earlier. When not exposed to air it keeps (as far as I can tell) indefinitely, at least on the scale of days and weeks.

I hope this helps anyone who wants to give this process a try.

I should add, by the way, that this formulation doesn’t work - at all - on inkjet paper; no image or only a faint image appears.

There are many many further ideas and improvements that are described in several decades of publications and patents on this, so I've a lot more experimenting to do. If I find anything interesting, I'll post it here.

Nice tests, I was wondering how much does the exposure on the negative impact the results on the receiver sheets? Is that also a way to tweak the results, or would that not work because you sit in the shoulder of the density and so loose contrast?

>I was wondering how much does the exposure on the negative impact the results on the receiver sheets? Is that also a way to tweak the results...

I think the short answer is yes, no, and maybe.

But the goal of this experiment was to look at the results of two toners, particularly in terms of Dmax and colour tone. There still isn't an exposure "curve" that will suit general photography. Increasing the exposure of the negative will move grey to light grey, dark grey to grey, and open up some of the shadows a bit. Either way, Dmax and colour which are (mostly, I think) functions of the chemistry aren't changed.

There are a lot of other variables to change to see what their effects are:

• choice of negative
• which developer(s)
• developer(s) concentration
• silver solvent choice (thiosulphate in this case) and concentration
• nuclei type and density
• nuclei emulsion thickness
• toner(s) type and concentration
• choice of base - hydroxide, here and pH

Compared to two centuries of knowledge accumulated and published about how to control and optimize standard black and white photography, what we know about how to control this is pretty sparse.

alecrmyers said:

I think the short answer is yes, no, and maybe.

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Thank you for the reply, I will let that sink in and think about it further. I can just imagine how they were in the Polaroid laboratories doing thousands of tests checking all these variables and more to optimize the process.

regards
Jan.

@alecrmyers : Just a stupid question perhaps, but I was wondering, would this work with a developer only ie not adding the fixer - thiosulphate to the process?

regards
Jan.

The thiosulphate is a silver solvent; it complexes and dissolves the silver halide and allows it to diffuse across to the receiver paper where the silver ions are reduced to metallic silver and precipitated. If you don't include a silver solvent you don't get any image on the receiver paper.

We know of thiosulphate as a "fixer" in traditional processing because by dissolving and washing away into solution any remaining silver halide it prevents "printing out" where that unexposed silver halide is slowly reduced to silver absent any developer, darkening the light areas of the negative. Fixer doesn't really "fix" the silver that was already developed, so the name is a bit misleading.

alecrmyers said:

If you don't include a silver solvent you don't get any image on the receiver paper.

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That is what I thought. OK, in my mind I still do not understand how it could work, but form practical examples I know it does. thank you!

alecrmyers said:

We know of thiosulphate as a "fixer" in traditional processing because by dissolving and washing away into solution any remaining silver halide it prevents "printing out" where that unexposed silver halide is slowly reduced to silver absent any developer, darkening the light areas of the negative. Fixer doesn't really "fix" the silver that was already developed, so the name is a bit misleading.

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So to get grasp of the chemical process, it only works when the distance between the negative and the accepting layer is very narrow. It requires the unexposed silver to get mobilized by the thio-sulphate to move away, it can only go to the layer of the receiving paper and then condenses back to silver for some reason. The accepting sheet must initiate this condensation and be capable of retaining it in its surface so density can build and a positive is created. (sorry for the simplification) Development on the negative must take place because you need the reverse to mobilize the silver to move to the accepting layer. You are not necessarily trying to develop that negative but it is a by-product of the process to get the remaining silver moving. If there would be another way to move the silver and get a positive, the objective is the positive and not to fix the negative. Hope I understand it now.

There are two competing reactions: the dissolution of unexposed silver halide, its diffusion across the thin layer of developing fluid, to the receiver sheet, and it's reduction and precipitation there, vs. the reduction of the exposed silver halide in situ in the negative.

I have another method of producing nucleation particles to make a receiver sheet, similar to my post of May 5, this time using the photolytic reduction of palladium chloride by oxalic acid under ultraviolet light:

• 2g - 0.1% palladium chloride (dissolve 100mg in 100ml 0.1N HCl)
• 2g - 1N oxalic acid (Amazon or hardware store) (6g in 100g water)
• 6g 0.5% PVP
• expose to UV - 365nm lamp for 5 minutes

solution turns from yellow to brown indicating the formation of palladium nanoparticles

• add 20g of 6% gelatin and plate as previously (with 100 micron wire style bar)

I believe one could also use the photolytic reduction of silver nitrate with citric acid. I have a feeling this works under UV as above and it also works in a microwave oven.

At this point here is a brief summary of what I have discvered by experiment and been taught by a shelf full of patent literature:

Developer

There seem to be two broad attacks to providing a developer (halide reducer).

The first is the traditional phenols, such as hydroqunione, metol, and I'll thrown phenidone in there, accelerated by citric or ascorbic acid. Also in this pile are some Polaroid "specials" such as 2,3,5-trimethyl-p-aminophenol, 2,3,6-trimethyl-p-aminophenol, and 4,6-diaminocresol. These are not available off the shelf and will have to be synthesized. I'm working on creating some of them.

The second attack on the developer problem is via one or more of a range of organic amines (almost all of which stink of rotten fish). For example, this post: https://www.photrio.com/forum/threa...m-with-dried-out-chemicals.71511/post-1001556. The advantage of the amines is that they are volatile and so evaporate as the print dries. Polaroid used both approaches, in different peel-apart products.

Silver Solvent

Other than the developer chemical(s), the developing paste needs a silver solvent component as discussed above. Land moved away from thiosulphate because if you're not washing your print the thiosulphate ends up causing stains. There are a bunch of polaroid patents for using cyclic imides for this purpose - if you look in the post I quoted above you'll see uracil, which is one such. Other examples are cyanuric acid (a swimming pool chloride preserver) and succinimide. I haven't had much success, yet, with these. But I'm still working on it.

Receiver Paper

I've found several different ways to produce nucleation particles, several described above, and any of which will work when plated in gelatin. I haven't had a lot of success with using a layer of silica, or alternatively using a layer of partially hyrdrolyzed cellulose acetate. More work to do there.

alecrmyers said:

The thiosulphate is a silver solvent; it complexes and dissolves the silver halide and allows it to diffuse across to the receiver paper where the silver ions are reduced to metallic silver and precipitated. If you don't include a silver solvent you don't get any image on the receiver paper.

We know of thiosulphate as a "fixer" in traditional processing because by dissolving and washing away into solution any remaining silver halide it prevents "printing out" where that unexposed silver halide is slowly reduced to silver absent any developer, darkening the light areas of the negative. Fixer doesn't really "fix" the silver that was already developed, so the name is a bit misleading.

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"Fixer" as in image is fixed, meaning stabilized - goes back to early days when before hypo came along the image was rather transient if not store in dark.

:Niranjan.

nmp said:

"Fixer" as in image is fixed, meaning stabilized - goes back to early days when before hypo came along the image was rather transient if not store in dark.

:Niranjan.

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Yes. In traditional photography thiosulphate fixes the image. It doesn't "fix" the silver though - the silver doesn't need fixing. In the context of diffusion transfer printing, thiosulphate isn't a fixer at all. So when Jan asks about "not adding the fixer - thiosulphate to the process" his language suggests he's not clear about what's going on. DTP images don't need to be fixed.

Hi @alecrmyers

Firstly, I just wanted to say a huge thank you for sharing all this. I think like myself a few of us over the years have been trying to find a good resource for this. Obviously costs can be prohibitive so although there's more experimentation this does help people start (I am also aware this isn;t cheap but would be a lot more without your guides and notes). Anyhow, I just wanted you to know I have been following all of these note and purchased everything to try and do this myself minus the 1phenyl-5-mercapto(1h)tetrazole which I have not found for sale anywhere yet but seems that shouldn't stop me getting results. The items should arrive over the next couple of weeks. I'll share progress as I go if you like and see what happens.

I would love to try this with film negative also and will be trying that in the tests so if you have any advice for that other than just giving it a go, do let me know.
Quickly, do you think the receiver paper somehow can be made to last a while or have any ideas what might improve that to be longer? I see your notes on it lasting only a couple of days very max but more likely hours due to the zinc sulphide.

Thanks so much, excited to give this a whirl.

Thanks for giving it a try. I'm looking forward to hearing how it goes.

Ayupchap said:

I see your notes on it lasting only a couple of days very max but more likely hours due to the zinc sulphide.

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On the receiver paper: I don't think I found that it only lasts a couple of days - a week or more for sure. I haven't tested a two year lifetime like you'd want in a commercial product, obviously.

At this end I'm working on some different developer chemistry. Also I've had some success using uracil as a silver solvent in place of thiosulphate. And I'm still looking at layers of celulose acetate as alternatives to gelatin but without anything good to report yet.

Hey @alecrmyers hope all is good.

I wanted to give you an update on my progress as its been a few weeks and also searching for some help or guidance if at all possible.
Firstly I bought and received all the chemicals, instruments needed to make the receiver and developer. I have actually tried a couple of different methods.
Firstly I tried the first approach you shared which used the paper coating but a 3% gelatine receiver layer. I used epson glossy photo paper. I also used your first posted developer recipe of:
60g 2% CMC (optionally 1%)
1.2g sodium hydroxide
1.2g sodium sulphite
0.3g sodium thiosulphate
Mix well then
0.5g ascorbic acid
1.0g hydroquinone
I could see it trying to work but had real issues with the spread, like big time and still am BUT I did get these results from it (I al using ilford paper as the negative similar to yours).




I got one other which is similar of a different photo. I can assure you I was very excited to get this and the other (I will post later as i am hitting a limit of photo size).
Anyhow. Getting a spread has been a nightmare. I tried 3M contractors tape on the reciver edge and managed to put the negtiave over that but that didn't do great.
I even used my polaroid 8x10 rollers with the constructors tape inbetween and thats how i got the result above but thats by far the best I have got it. I also tried a hard surface and contractor tape between the receiver and negative and that also gets porr results even if i get a full negative development, the image transfer is an issue.
I am now trying another recipe for the developer you mentioned which is:
29.4g water
0.6g CMC
0.6g sodium hydroxide
0.6g sodium sulphite
0.5g sodium thiosulphate
0.5g hydroquinone
0.1g metol
25mg Cysteine HCl
The receiver for this one was using a 6% gelatine solution. I am also using a 25 micron spread using a similar device as you to do so.
I have got poor spreads on the receiver although the negative is getting a near full spread and developing. I am not sure whats wrong but really having trouble with the gap. I wondered if you could give any help. I also had the following questions:
In you description you are using a pet plastic for guide rails. I thought these were in between the negative and positive sheet but it looks like in your video the papers are just pressed on top one another with the rails either side. Can you confirm how you are doing this?
With the 2nd recipe I mention, can you confirm that a treated epson glossy photo paper should work fine? You mention inkjet paper would not work.
Is there a better paper i could use? If so do show a link and I will try that out.
What tape might be better than 3m contractors tape? I also tried a 3M 300L double sided tape thats meant to be .06 or 0.07 but that didn;t do any good either.
Anyhow I am now fully invested in getting this go work and finding a method to get more consistent results. Any help would be much appreciated. I was trying to privately message you but I have not hit enough posts to be allowed to do so it seems so feel free to reach out to me there also if you like.

Also @alecrmyers heres another photo from my first batch

My latest batch got even poorer results! But you will see the spread on the negative was stronger

Ayupchap said:

You mention inkjet paper would not work.

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Just my two cents, but inkjet paper is designed to soak liquid directly into it. If you put a piece against your tongue, it will stick as it draws the moisture in. That could make spreading developer problematic.

What if you tried fixed-out rc photo paper?

Don_ih said:

Just my two cents, but inkjet paper is designed to soak liquid directly into it. If you put a piece against your tongue, it will stick as it draws the moisture in. That could make spreading developer problematic.

What if you tried fixed-out rc photo paper?

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I am using photo paper rather than inkjet myself @Don_ih theres some glossy inkjet paper that was mentioned working before (not normal inkjet paper commonly used I think). I am actually using eposon photo paper for printers which is glossy and apply the receiver on that.

I'm thrilled you got some images. Well done.

As far as the video goes, I've moved on from that, so what I described later (and here) isn't what's in the video.

As far as paper goes: at the moment I'm using "plastic paper" from Amazon. It works well. The absorbent coating on inkjet paper is an impediment.

I've not tried (and I'm not going to try) fixed out RC photo paper. There's no point wasting a piece of an existing photographic product - you might as well do a regular print on it. Secondly there's enough residual silver iodide on fixed-out photographic paper that you don't need to coat it at all. Again, that's not the project I have in mind.

To spread the developer between receiver and image you must use an engineering-flat surface, and an engineering-straight roller. Regular things that look and feel flat and straight just aren't good enough. I'm using a granite surface plate from Amazon (grade B seems ok) and a short length of precision turned chromed steel tube designed as a rail for a 3d printer, from Aliexpress. Land wrote that his products use developer spread to about 3 mils (76 microns), the same as the plastic film I'm using for rails. That means your surface must be flatter to a considerably better than 3 mils edge-to-edge along it's whole length, and your roller must be straighter to a considerably less than 3 mils. Otherwise you'll get high and low spots causing uneven development and "bald patches".

Right now what I'm using goes like this: receiver goes face up on the granite plate; rails go down the edges of the paper on top; bead of developer goes across the top of the paper between the rails (like this: https://www.photrio.com/forum/attachments/fullsizerender-1-1-jpeg.370602/) then the exposed negative goes on top, overlayed over the developer at the top and overlaying both rails on the side.

Then lower the cover, and roll the precision roller down the surface plate.

Keep up the good work!

(Edited to fix my confusion between mils and microns)

Thanks @alecrmyers, appreciate your additional insights here.

I should add, I have not used RC paper for the receiver at all. I am using it for the negative element to diffuse from. My photo paper is actually epson photo paper for the printer I have coated. With regards to the plastic paper, are you referring to the waterproof paper for laser printers?
Maybe you wouldn't ming also letting me know if you have had more success with a receiver spread of 25 microns or 100 microns using the roller? Maybe it hasn't mattered? Also whether you have found a 3% gelatin or a 6% gelatin has been better.

I am going to investigate improving rail sizes with much flatter equipment. In your photo of your rails that must be thicker than 3 microns right? If so what are you finding acceptable for results?

Again, appreciate all your help. I am going to continue experiments here and let you know how I get on.

100 micron coating bar (not a "roller" as it doesn't roll) - either gelatin should work.

To disambiguate: the photo I linked to shows the use of 3 mil film as rails (that's 3 thousandth's of an inch). t's cut from 3 mil laminating pouches, and I've verified the thickness with a gauge. Apparently that's 76 microns. Sorry for the error.

I don't think you'll get anywhere with rails that thin until you have a flat surface to use. This is the one I bought: https://www.leevalley.com/en-ca/sho...ring/32526-granite-surface-plate?item=88N8501 - it claims to be flat to 0.2 mil.