Polyacrylamide Gels & Resins

Annie · Oct 23, 2005

I have been snooping around in the Kodak paper patents this morning at freepatentsonline and among the list of their sizing materials for increasing wet strength and smoothness are polyacrylamide gels and resins... does anyone happen to know where I can get some in small quantities... does anyone know about their solubility when dry... anyone tested these? Thanks!

Photo Engineer · Oct 23, 2005

Annie, using them for sizing anything that needs to be wet processed will result in the coating sliding off the support.

You cannot harden most of those compounds. Unless the polymer is specifically hardenable, it is not suitable. I was never able to harden polyacrylamide.

It is usable for ink jet work and for instant imaging as the ressults never get wet enough, but if you wet some inkjet papers, they slide off the support as well. I've done it.

PE

Annie · Oct 23, 2005

Rats!! Thanks PE!!

Photo Engineer · Oct 23, 2005

Annie, been thinking about this. I realized that I should have mentioned that these polymers can be mixed with gelatin and sometimes you get the best of both worlds.

So, let me encourage you to do some experimentation. Who knows.....

PE

Annie · Oct 23, 2005

Yikes... only 27 views all day and most of them mine ... I must be the Queen of the Ignore Lists... sheesh.... guess it's back to whipping up egg whites maybe I'll add a little celquat this time!! cheers... hmmmm...anyone doing an albumen layer size under Pt??

Annie · Oct 23, 2005

PE ... my only APUG photo pal!! I have been thinking about this also and I discovered that polyacrylamide is also used in plant hydration and you can get it in small quantities at garden shops... I am going to try just a touch with a modified albumen size I am messing with and see what happens... so far with the albumen I have been able to bump up the Dmax a touch on a very smooth extinct Kodak paper I am using for Pt.... wish me luck!

Photo Engineer · Oct 23, 2005

Luck Annie.

Keep in touch. I'll try to help where possible.

Never give up. In photography, things are never as they first seem. The phase of the moon keeps changing. ~smiles and grins~.

PE

Jarred McCaffrey · Oct 24, 2005

Polywhoziwhatzit? Can someone post a brief explaination of what these are and why they are important for alt photo? I'm only familiar with gelatin sizing. Thanks!

Jorge · Oct 24, 2005

Photo Engineer said:
Annie, using them for sizing anything that needs to be wet processed will result in the coating sliding off the support.

You cannot harden most of those compounds. Unless the polymer is specifically hardenable, it is not suitable. I was never able to harden polyacrylamide.

It is usable for ink jet work and for instant imaging as the ressults never get wet enough, but if you wet some inkjet papers, they slide off the support as well. I've done it.

PE

How is the polyacrilamide when dry? This might be a good coating for dried prints to bring back the "life" they have when they are wet. This of course if it does not yellow out, which I have the feeling many acrylates do....

Photo Engineer · Oct 24, 2005

Guys, many polymers can be substituted for gelatin in photo products. The problem is that they must be hardenable to survive the wet processing steps or they can be washed off the support.

Being hardenable is not normally the case. So, they must be chemically tailored for allowing hardening to take place. For example, formaldehyde reacts with gelatin to harden it, but formaldehyde will not react with most polymers.

OTOH, a polymer is often resistant to yellowing. So, they might be usuable as an overcoat on a dry print to give it a 'wet' or glossy look. This is the method used in some spray on treatments for prints.

I cannot comment on the utility of any particular polymer for potential use in or on a photographic material. I can just say try it and see. Many of these are rather hard to come by though, at least in their pure form.

They are made by initiating a chain reaction in a solution of the monomer so a solution of the monomer called acrylamde can be polymerized into polyacrylamide which turns it from a thin organic liquid into a thick organic polymer akin to man made gelatin. (with the drawbacks above). Mixing acrylamide with other monomers and initiating that chain reaction can add hardenable sites to the polymer and make it more like gelatin.

Too much chemistry, right? Lets forget it for now.

Polymers can be good or bad. They have to be judged by trial and error for being useful in a photo material. You have to do the grunt work.

Have fun.

PE

Annie · Oct 24, 2005

Jarred...Virtually since the beginning of papermaking various sizings and coatings have been utilized to impart papers with variations in surface structure. Classic coatings and sizings are many... proteinaceous materials (gelatins & glues), starches, carboxymethyl cellulose, gums, waxes, clays, casein, kaolin, lime, baryta (blanc fixe) etc. etc. employed singly or in combination. In the last century many synthetic sizings and coating application techniques have been developed that have greatly increased the variation of papers and surfaces available. Polyacrylamide gels and resins are among these synthetic sizings.

What they have to do with Alt processing may turn out to be indeed nothing...

I am just investigating them because I am seeking a very specific surface for my Pt/Pd printing that is not available in the usual papers. I am trying to achieve a lustrous smooth surface that has a greater luminosity and will carry delicate detail.

Jorge... indeed most of the synthetic acrylic coatings that printers are now using will indeedyellow.. the polyacrylamides have been used in papermaking by Kodak for a while now (raw paper not in the coating) ... at least it is listed in the patents and the papers do not seem to be yellowing.... mind you the amounts are comparatively small. I have some gel crystals here now and they are not yellow.

PE... any thoughts on this?

Annie · Oct 24, 2005

Yikes... PE.. I see I am writing while you were posting....... anyway if I get any results that could be of benefit to anyone I shall post here... Cheers Annie

Photo Engineer · Oct 25, 2005

Annie, the polymers used in papers often are often accompanied by strong antioxidants to prevent yellowing. These are called 'free radical chain stoppers'. They are often covered in a separate patent claiming just their antioxidant properties in papers and may not show up in the polymer patents.

Therefore, the plain polymer may or may not yellow.

I have coated a lot of these, both hardenable and non-hardenable and they all have good and bad points. One of the hardest ones to deal with is the fact that they don't chill set. Coating on a machine is therefore difficult, but when hand coated, they can work out just fine. So something I would reject in a factory setup might be fine in a home darkroom.

That is why I said 'trial and error' because there is no rule or advice I could apply. I think that the only thing I could suggest is to try to keep the viscosity high for ease of coating. It would get too runny at low viscosity.

You can do this by getting a polymer with a high molecular weight (long chain length) or by making your polymer solution very concentrated before you coat (usually 10% or higher). You could also do this by spreading out a thin layer and allowing absorption of moisture to thicken up the layer.

Above all, it should not run when the coating is hanging to dry or lying down to dry or it will ruin the print, and that is my point about viscosity.

And, if the polymer will not harden, the print must be protected from moisture. Even contact with wet fingers will leave unsightly marks.

OTOH, some beatiful results might be obtained by the application of the right vehicle to the coating or as an overcoat.

You may want to try a carbowax 14xx or carbowax 3xxx series. These are clear stable polymers that dissolve in water and dry with a rather clear sheen.

PE

avandesande · Oct 25, 2005

I used to work at a plant that made polyacrylamide by the ton. It used as a water-treatment chemical. Eventually our company was purchased by ciba-geigy. We also made a bunch of water-soluble polymers used to size paper, such as poly-DMDAAC, and poly-acrylic acid which is used in diapers (those swell up beads)
If you are persistent you could find a distributer that would be willing to send you a sample.

Annie · Oct 26, 2005

The Blob That Ate Vancouver Island!!!

WOW... do these gel crystals love water... it is absolutely fascinating! I think it may be the resin I need.

David A. Goldfarb · Oct 26, 2005

So you'll have RC pt/pd prints? Out of curiosity, have you tried coating a polyester base, like what is used for the Ilfochrome and Fuji supergloss materials?

Annie · Oct 26, 2005

David A. Goldfarb said:
So you'll have RC pt/pd prints?

Many printers use natural resins and gums as an overcoat so I guess RC/Pt has existed for a while... I am not aiming for 'supergloss' just trying to gain extra luster and luminosity without too much reflectance and glare ( I am making small handcrafted books at the moment so glare is an issue) thanks for the suggestions... Cheers!

Gerald Koch · Oct 26, 2005

Either Ansel Adams or one of his contemporaries recommended using lithographers varnish to protect and add luster to matte surface prints. If I remember rightly the varnish was diluted with 4 or 5 parts of turpentine. The mixture was applied to the print with a cotton ball. As much of the varnish as possible was then removed using a lintfree cloth. A second or third application can be made to produce a shinier surface. I have prints that are 40 years old where I used this technique and it does add lusture and protection.

Photo Engineer · Oct 26, 2005

Annie said:
WOW... do these gel crystals love water... it is absolutely fascinating! I think it may be the resin I need.

Annie, this is exactly one of their problems as well.

After you coat them on your print, they will still 'love' water and may act unpredictably to changes in humidity. They certainly will tend to wash off or come off on damp fingers.

Water insoluable polymers such as a varnish from turps will not exhibit this property as noted here.

Coating on RC presents other problems, as the RC is either fixed out photo paper with a thick gel 'size' which is the residue from the photo emulsion, or is raw RC which must be sized with a thin gel pad or wash to promote adhesion. These two types of RC exhibit different coating and chemical properties. Both of these, in turn, exhibit different properties than FB papers. You cannot coat on unsized or unsubbed RC support. The coating will wash off during processing.

The main difference in these is that the FB paper acts as a large 'sink' for absorbing the chemistry you coat and the chemistry you coat is in intimate contact with the paper fibres and chemistry. In RC that was formerly photo paper, the 'sink' is intermediate and contains traces of chemsitry from its use as a photo paper. The RC that just has a thin size on it behaves more like a film support in that there is no 'sink' for chemistry and everything is on the surface. You can get tacky coatings and even crystal formation on this type of support.

PE

Annie · Oct 26, 2005

PE...Having the emulsion engaged in intimate contact with the paper is essential ... for me having the image floating on an RC coating is not an acceptable proposal.

All I am really trying to do is bump the Dmax and gain some luminosity by adjusting the sizing in a paper that I have found to be wonderfully smooth with superior wet strength but with inconsistantcies in its absorption of the Pt emulsions and dry down... I am confident that eventually I will discover the 'sweet spot' for my paper. Thank you for your wonderful answers... I am learning much from you... Cheers Annie

Photo Engineer · Oct 26, 2005

Annie, thanks for the nice comment. I try to help as much as possible.

Typically glossy papers give higher dmax than matte, but it is very hard to get glossy surfaces on plain paper. The Baryta or Titanox and RC supply the gloss. A process called calendaring helps (hot press rollers with tons of pressure).

Usually, you cannot add a gloss afterwards and increase dmax due to physical limitations. The best gloss is obtained if the smooth surface is underneath the photographic image.

A glossy baryta where the chemicals are in intimate contact with baryta might help, but IDK how it would work with Pt/Pd. With silver halide emulsions is gives a nice slick finish on both Baryta and RC. There have been comments either way regarding baryta with Pt/Pd and RC as well IIRC.

PE

Kerik · Oct 26, 2005

Annie,

I'm curious - what paper are you using?

Annie · Oct 26, 2005

Kerik... I am using Kodak PX-3001 CD ( I think this is the older version of P-Max Fine Art) with the emulsion removed... even after all the wet time and chemical abuse of removing the emulsion when you look at the paper surface under a loop there is virtually not disruption of the paper fibers... photographic papers recycled in this manner are probably not a viable consideration for most printers but I keep returning to it because I cannot get what I am seeking from other papers I have tried so far.

I had hoped there would be some promise with the Bergger paper the Apug co-op was trying to obtain but when I checked my notes I found the 'Forte' paper base had problems... but as someone said perhaps the paper has changed.

Cheers Annie

.... let me know if you want to see my paper I can pop a few sheets in the post if you like.

Annie · Oct 26, 2005

Kerik... I was just wondering I know you do 'gum over' would something like 'gum under' be feasible... this would make my whole paper issue moot.

What is the surface quality of a 'gum over' print... it is lustrous?

Kerik · Oct 26, 2005

Annie said:
Kerik... I was just wondering I know you do 'gum over' would something like 'gum under' be feasible... this would make my whole paper issue moot.

What is the surface quality of a 'gum over' print... it is lustrous?

The gum layers do add some luster to the surface, moreso in the shadows where the gum is thicker than in the highlights where it is thinner or absent. I've never tried this, but you could do an unpigmented, hardened gum layer over the platinum print:

Mix equal portions of potassium dichromate (10%) and a nice clean gum arabic, coat the print, dry, expose to UV light for a few minutes, soak face down in plain water for 15 or 20 minutes (change the water a few times). Let the print dry. If there is any residual dichromate, soak the print in a solution of 1% potassium metabisulfite for a couple minutes - in fact, do this anyway just to be sure all the dichromate is cleared, followed by a final 10 or 15 minute wash. This should give you an even, hardened clear coat of gum arabic over your pt print. If you don't use a nice, clear gum, this layer may have a slight tint to it, however. While this sounds like a lot of work, done on a production line basis, it could be done very quickly and efficiently. Hmmm... maybe I'm just going to have to try this myself!

It's hard to do gum under (I like that name!) because the pt sensitizer will not adhere well to the gum. You would probably need to lay down size over the gum for the sensitizer to stick. I presume you've tried Renaissance Wax as a final surface treatment? It helps some with a sheen, but it's subtle. Even more sublte is Liquitex Acrylic Gloss Medium diluted ~8:1.

Polyacrylamide Gels & Resins

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