Quote Originally Posted by R Shaffer View Post
So I gave it go yesterday making a Lippmann Plate.

It looks like I have a ways to go to get better color rendition, but I am stoked I was able to record a standing wave pattern in the emulsion. I used GEO-03 holographic plates. Hardened the emulsion with a Glyoxal soak and developed in Lumiere Pyrogallol-Ammonia developer.

I definitely altered the emulsion too much in processing, which is why the white table is blue & the red roses in the middle of the table are not red. But the green plants at the top left & bottom right are almost green & the blue turtle on the table is very blue.

If anyone has any suggestions on how I might reduce altering the emulsion in processing, I'm all ears.

Hardener (6min): 5ml Glyoxal, 1gr KBr, 2.5gr So. Carbonate to make 500ml

Developer (2min): Sol A - 1gr Pyrogallol, 100ml Alcohol. Sol B - 10gr KBr, 100ml H2O. Mix 20ml A + 30ml B + 140ml H2O + 10ml Sat. Ammonia

Rinse 10min & soak 2min in LFN ( 4drop in 500ml approx )

All at 60deg F, except the developer seemed to be having a reaction and warmed itself to 68deg.
Great results, congratulations!

I don't know whether the two hardeners, formaldehyde and glyoxal, act at similar speed regarding emulsion hardening.
Maybe glyoxal takes much longer.
What about baking the plate right after the photographic exposure and prior to liquid processing? I remember having done baking (without adding any specific hardening agent) with a couple of gelatin based materials, like dichromated and ferric gelatin. They required a relatively long time of treatment - say, 45 - 60 minutes at 120C. So this definitely complicates the whole process.

Regarding your developer I wasn't aware (anymore) it had such a high KBr concentration. As PE pointed out KBr also acts as a silver solvent. By the way there are colloidal developers that contain but KBr as the silver solvent. Moreover, in my reply to your post at the holography forum I forgot to mention that ammonia is both a silver solvent and a very strong alkali. So increasing/decreasing its amount makes it very tricky in respect to solvent/developing action.
So switching to another developer may be a better option I guess. There's an alternative to the GP-2 type of developers. I was involved with people from the Russian holography forum to set up a developer which replaces the ammonium thiocyante by sodium thiosulfate. I can't seem to find that link anymore. The whole thing was done with two stock solutions, one containing the thiosulfate only (I believe).