Making 'sticky' emulsion

[ThePhotoChemist]

Alright hear me out on this one. I was thinking again about a replacement for the mercury mirror in Lippmann plates (as one does on boring days at work). I found out Hans Bjelkhagen had successfully laminated silver foil against the back of photopolymer. I had assumed he had used a laminating machine, however when I questioned him, he elaborated that he merely carefully applied the foil to the emulsion with some rolling. It seems that this photopolymer emulsion he used was somewhat stickier than a standard silver gelatin emulsion.

I wonder, is there any sort of additive one could use that would cause a dry plate to still be somewhat sticky, allowing for a similar adhesion?

 

[Photo Engineer]

Ask him?

 

[ThePhotoChemist]

The material was a commercial photopolymer made by DuPont, not by him personally.

 

[Photo Engineer]

Is there any problem with using that polymer then? It should be available.

PE

 

[ThePhotoChemist]

Well, his results with the photopolymers are neat looking, but they don't really look as good as classical silver-gelatin based Lippmann plates. I was hoping to adapt his method with the photopolymer and apply it to the Lippmann plates that I'm familiar with making. Plus, its much more fun to make these myself, rather than buying them already made!

 

[Photo Engineer]

Well, OTOMH, the only sticky polymers I know of were proprietary to EK and were used as binders or as gelatin extenders.

In that regard, perhaps a PVP or PVA might help.

PE (no relation)

 

[nmp]

Alright hear me out on this one. I was thinking again about a replacement for the mercury mirror in Lippmann plates (as one does on boring days at work). I found out Hans Bjelkhagen had successfully laminated silver foil against the back of photopolymer. I had assumed he had used a laminating machine, however when I questioned him, he elaborated that he merely carefully applied the foil to the emulsion with some rolling. It seems that this photopolymer emulsion he used was somewhat stickier than a standard silver gelatin emulsion.

I wonder, is there any sort of additive one could use that would cause a dry plate to still be somewhat sticky, allowing for a similar adhesion?

Are you looking to replace the gelatin completely with a new polymer that dries to stickiness or coat the existing gelatin layer with something that will tick to the silver foil?

 

[Hologram]

Alright hear me out on this one. I was thinking again about a replacement for the mercury mirror in Lippmann plates (as one does on boring days at work). I found out Hans Bjelkhagen had successfully laminated silver foil against the back of photopolymer. I had assumed he had used a laminating machine, however when I questioned him, he elaborated that he merely carefully applied the foil to the emulsion with some rolling. It seems that this photopolymer emulsion he used was somewhat stickier than a standard silver gelatin emulsion.

Yes, absolutely, it's much stickier than a simple AgX gelatin layer. The material mentioned by Bjelkhagen is DuPont's Omnidex. But I think in the early 2000s DuPont stopped selling it freely - focussing on security businesses instead. In the meantime Bayer (Covestro) has come up with a volume holographic photopolymer. They have panchromatic films. You may take a look at http://litiholographics.com, they sell panchromatic photopolymer plates - which some believe, rely on Bayer materials.

These photopolymer layers remain tacky until polymerized. So it's not difficult to optically contact a mirror with them prior to the light exposure. In order to be able to remove the polymerized layer from the mirror, you may treat the mirror surface with some silane or PTFE stuff - Rain-X may work as well.

One chief difficulty with these films stems from their layer thickness (compared with the very limited coherence length of "natural" light). Usually they are 20um or thicker. So blue recordings tend to become very tricky. It would be far better to have a liquid photopolymer solution and do the coating yourself. You may then produce very thin layers - maybe around 4um. Index modulation of these photopolymers should be high enough to get relatively good image brightness. Perhaps Covestro would be willing to send you some liquid...

I wonder, is there any sort of additive one could use that would cause a dry plate to still be somewhat sticky, allowing for a similar adhesion?

For AgX gelatin? Why not add some glycerol, glycols etc.? Of course it would swell the emulsion to some extent prior to the photographic exposure. To prevent any wavelength shift, you'd therefore add some swelling agent to your Lippmann photographs at the end of the process as well. The good news is that this would greatly simply the display. The bad news though is that it might speed up printout.

 

[Hologram]

Well, his results with the photopolymers are neat looking, but they don't really look as good as classical silver-gelatin based Lippmann plates. I was hoping to adapt his method with the photopolymer and apply it to the Lippmann plates that I'm familiar with making. Plus, its much more fun to make these myself, rather than buying them already made!

Having seen your amazing progress with Lippmann photography and autochromes, making photopolymers on your own wouldn't be that difficult.

 

[ThePhotoChemist]

Are you looking to replace the gelatin completely with a new polymer that dries to stickiness or coat the existing gelatin layer with something that will tick to the silver foil?

I'm hoping to use an additive to make the gelatin emulsion slightly sticky after drying. I feel replacing the gelatin entirely could lead to a whole host of other problems that I don't want. I don't think coating the existing gelatin with something sticky would work either (in this application), since any gap between the gelatin and the mirror will disrupt the interference pattern.

Thanks PE and Hologram for the suggestions! I have both glycerin and PVA hanging around that I can play with. I'll play around with those and see what I can get!

Having seen your amazing progress with Lippmann photography and autochromes, making photopolymers on your own wouldn't be that difficult.

You're far too kind! It's an interesting thought though, and might be fun to look into! Thanks for the ideas/encouragement!