Search found 85 matches

by Martin
Tue Sep 03, 2019 9:56 am
Forum: DCG
Topic: Ferric ammonium oxalate tests
Replies: 118
Views: 17464

Re: Ferric ammonium oxalate tests

I usually just add few drops of 10% soduium lauryl sulfate solution and it helps for gelatine and PVA emulsions enough to stay on the glass unless additional reprocessing with longer water exposure used. That's interesting. Usually surfactants are said to have a negative impact on layer adhesion (I...
by Martin
Thu Aug 22, 2019 2:40 am
Forum: General Holography
Topic: D.I.Y. holographic photopolymer
Replies: 26
Views: 3523

Re: D.I.Y. holographic photopolymer

Yes, exposed areas are water resistant, unexposed ones get washed off, like photoresist. IPA baths are useless, it has no effect. OK. So in order to record reflection holograms (and apply DCG-like processing) you'd have to pre-harden/crosslink the PVA prior to the holographic exposure. But using ge...
by Martin
Wed Aug 21, 2019 2:42 am
Forum: General Holography
Topic: D.I.Y. holographic photopolymer
Replies: 26
Views: 3523

Re: D.I.Y. holographic photopolymer

After reducing amount of sensitizer i've obtained some weak diffraction patterns from PVA + speedball sensitizer with transmission hologram copy, but it is really bad quality - i barely see some edges of shiny objects. Looks promising still (i like its simple developing process - just few minutes i...
by Martin
Sat Aug 03, 2019 8:47 am
Forum: DCG
Topic: Ferric ammonium oxalate tests
Replies: 118
Views: 17464

Re: Ferric ammonium oxalate tests

I've encountered this kind of problem many times. I thought it was due to a defective coating or a layer of insufficient thickness.
by Martin
Tue Jul 30, 2019 9:49 am
Forum: DCG
Topic: Ferric ammonium oxalate tests
Replies: 118
Views: 17464

Re: Ferric ammonium oxalate tests

Interesting, that with very thin emulsion - i get coloured surface in last IPA bath but it disappears at drying instantly. Not sure if that is UV (or even IR shift?) It's UV shifted. as usually it takes quite time at drying to see colors moving towards violet. Of course, it is possible that thin em...
by Martin
Thu Jul 18, 2019 2:49 am
Forum: DCG
Topic: Ferric ammonium oxalate tests
Replies: 118
Views: 17464

Re: Ferric ammonium oxalate tests

RainX's leftovers (from mold coating) on emulsion - on last run i've noticed that water comes off plate very quickly on most of area. Washing in IPA does remove that effect, i think it can affect developing/hardening/swelling. You can do mold coating without Rain-X treated glass plates: simply repl...
by Martin
Mon Jul 15, 2019 2:00 am
Forum: DCG
Topic: Ferric ammonium oxalate tests
Replies: 118
Views: 17464

Re: Ferric ammonium oxalate tests

Not to be a bummer on this thread, but my experience using the 407 nm laser, the dcg holograms are dim looking due to our eyes not being sensitive to this deep blue/purple range. It’s difficult enough to try and get a good DCG hologram w a 530nm or 488 nm laser. You might try and find a more suitab...
by Martin
Fri Jul 12, 2019 10:11 am
Forum: General Holography
Topic: D.I.Y. holographic photopolymer
Replies: 26
Views: 3523

Re: D.I.Y. holographic photopolymer

perhaps i should try again with smaller concetration of the sensitizer and with transmission copy. Yes, that would be interesting. The speed was ok, comparable with my FEG experiments (with 405nm laser). It's a bit confusing as was supposed to be used with monomer (vinyl acetate in the emulsion can...
by Martin
Thu Jul 11, 2019 8:58 am
Forum: General Holography
Topic: D.I.Y. holographic photopolymer
Replies: 26
Views: 3523

Re: D.I.Y. holographic photopolymer

So you did try PVA (PVOH) + "Speedball diazo sensitizer, right? And, if I'm not misled, "Speedball diazo sensitizer" consists of the diazo stuff only (in form of a powder I assume), correct? In other words, this stuff is not identical with the "Speedball emulsion" (which is a liquid based on vinyl a...
by Martin
Sun Jul 07, 2019 9:04 am
Forum: General Holography
Topic: D.I.Y. holographic photopolymer
Replies: 26
Views: 3523

Re: D.I.Y. holographic photopolymer

Probably the most advanced work on PVA-AAM-MBA-TEA-dye has been done by the research groups in Dublin and Alicante. You can easily find their patents. E.g. look for "Suzanne Martin" + "photopolymer" + "hologram". Note that both groups attempted to replace acrylamide with less toxic monomers. As for ...