Search found 131 matches

by Martin
Tue Jun 27, 2023 7:56 am
Forum: DCG
Topic: question about PFG-04
Replies: 11
Views: 5579

Re: question about PFG-04

By the way, Martin, since you are the best-read person in holography that I know of, do you recall any studies concerning the hardening/dark reaction of gelatin/dichromate at high (~9) pH? I'm drawing a blank. Thanks. I'm not aware of any studies about that. Curiously, in 2008 Jeff and I discussed ...
by Martin
Tue Jun 27, 2023 7:53 am
Forum: DCG
Topic: Diazo (Speedball) gelatin hologram
Replies: 33
Views: 125522

Re: Diazo (Speedball) gelatin hologram

Martin, you've almost certainly seen this old 1978 report, but in case you haven't, it includes some info on diazo sensitization: https://erdc-library.erdc.dren.mil/jspui/bitstream/11681/11334/1/ETL-0128.pdf Also some mention of casein, and among other things, corn zein :) Yes, thanks, I've seen it...
by Martin
Mon Jun 26, 2023 3:59 am
Forum: DCG
Topic: Diazo (Speedball) gelatin hologram
Replies: 33
Views: 125522

Re: Diazo (Speedball) gelatin hologram

Here's the contents page for DCG and other materials. I used the method of carbon printing (chap 2.1b) to show it was possible to use DCG as a resist material. We recorded a thin hologram on DCG with depth < 1u, and then transferred the image to a piece of plastic by casting. We poured Norland onto...
by Martin
Mon Jun 26, 2023 3:50 am
Forum: DCG
Topic: question about PFG-04
Replies: 11
Views: 5579

Re: question about PFG-04

The commercial DCG holographic plates PFG-04 have been available for many years: https://www.geola.com/product/pfg-04-plates/ So people must be actually using them. But I have no recollection of seeing results being reported, or photos of the finished holograms. The interesting thing is that they h...
by Martin
Mon Jun 26, 2023 3:48 am
Forum: DCG
Topic: Diazo (Speedball) gelatin hologram
Replies: 33
Views: 125522

Re: Diazo (Speedball) gelatin hologram

Joy tells me that I tried to throw it out when we left Triple Take behind, but she rescued it; she knows it's somewhere, but doesn't know where. That sounds exciting. Would be nice to see it online some day. Martin, Joy found the book I inherited from Don Broadbent. non-silver.jpg I see, thanks for...
by Martin
Thu Jun 22, 2023 1:42 am
Forum: DCG
Topic: "bad" batch of dichromate chemical?
Replies: 6
Views: 3003

Re: "bad" batch of dichromate chemical?

That's a good point about the lower solubility of the potassium dichromate. When I planned to mix the stock solution, I knew nothing about it (compared to ammonium) but decided to do a quick check. I was shocked to see that, as you said, the solubility is about 1/3rd of the ammonium. So I decided t...
by Martin
Mon May 15, 2023 4:34 am
Forum: DCG
Topic: gelatin tests
Replies: 16
Views: 6188

Re: gelatin tests

Joe, you might remember Stojanoff's work... See e.g. https://www.researchgate.net/publication/238073312_The_effects_of_the_film_manufacturing_techniques_of_the_exposure_procedures_and_of_the_development_and_post-treatment_thermo-chemical_processes_on_the_holographic_properties_of_HOES_in_DCG_-_art_n...
by Martin
Sat May 06, 2023 4:34 am
Forum: DCG
Topic: Diazo (Speedball) gelatin hologram
Replies: 33
Views: 125522

Re: Diazo (Speedball) gelatin hologram

Joy tells me that I tried to throw it out when we left Triple Take behind, but she rescued it; she knows it's somewhere, but doesn't know where. That sounds exciting. Would be nice to see it online some day. I've been reading a great many papers on AgX, DCG etc. For AgX the specific impact from gel...
by Martin
Thu May 04, 2023 6:22 am
Forum: DCG
Topic: Diazo (Speedball) gelatin hologram
Replies: 33
Views: 125522

Re: Diazo (Speedball) gelatin hologram

I recently bought some photo gelatin from Phototypie in France, and noticed that (besides a nice variety of bloom strength Gelita photo gelatins) they offer DAS: https://www.phototypie.fr/en/reactifs-photosensibles/14-1-diazidostilbene.html#/21-weight-25_grammes This is interesting to me because it...
by Martin
Sat Dec 17, 2022 7:23 am
Forum: AgX
Topic: Printout revisited
Replies: 3
Views: 13613

Re: Printout revisited

I'd guess with ethanol it takes quite some time for the KI to diffuse into the emulsion - methanol would be much faster. Maybe you could even use a methanol/KI bath after your ethanol deyhdration steps.The big question though is if the process of converting AgBr into AgI does require at least a bit ...