D.I.Y. holographic photopolymer

Holography related topics.
Martin
Posts: 92
Joined: Sat Apr 04, 2015 2:36 am

Re: D.I.Y. holographic photopolymer

Post by Martin » Wed Aug 21, 2019 2:42 am

vasimv wrote:
Tue Aug 20, 2019 10:31 am
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 in water) but need to find a way to bleach the emulsion after developing in water as it blocks light and suitable only for amplitude holograms. Later i'll try it with gelatine too.

Sounds pretty interesting.
So did I get it right, your PVA + Speedball layer becomes water resistent after the holographic exposure?
If so, you might process the layer à la DCG - water bath + IPA dehydration.
For bleaching you might try potassium permanganate. It worked nicely with D.A.S. gelatin.

vasimv
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Joined: Tue Apr 23, 2019 2:16 am

Re: D.I.Y. holographic photopolymer

Post by vasimv » Wed Aug 21, 2019 12:48 pm

Martin wrote:
Wed Aug 21, 2019 2:42 am
Sounds pretty interesting.
So did I get it right, your PVA + Speedball layer becomes water resistent after the holographic exposure?
If so, you might process the layer à la DCG - water bath + IPA dehydration.
For bleaching you might try potassium permanganate. It worked nicely with D.A.S. gelatin.
Yes, exposed areas are water resistant, unexposed ones get washed off, like photoresist. IPA baths are useless, it has no effect. I just did keep in water for few minutes and then used heat gun to remove water from surface for 20-30 seconds. Easy to process but will create problem for bleaching as the agent won't get into emulsion. I guess, i need to reduce speedball diazo sensitizer's amount further.

Martin
Posts: 92
Joined: Sat Apr 04, 2015 2:36 am

Re: D.I.Y. holographic photopolymer

Post by Martin » Thu Aug 22, 2019 2:40 am

vasimv wrote:
Wed Aug 21, 2019 12:48 pm

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 gelatin instead of PVA might be much easier...
vasimv wrote:
Wed Aug 21, 2019 12:48 pm
I just did keep in water for few minutes and then used heat gun to remove water from surface for 20-30 seconds.
Most likely this will destroy the holographic *fringes".

dannybee
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Re: D.I.Y. holographic photopolymer

Post by dannybee » Sat Aug 24, 2019 12:41 pm

I have worked with pva in both silver and dichromate , its sounds like the speed ball (DIAZO sensitizer) is acting like a crosslinker, I've wanted to try this too, if it is a crosslinker in your pva you should see a weak image shortly after exposer with no processing (just like dcgpva) you could also include a dye with a electronic doner (tea) , then use fix just as in dcg and process just like a dcg. and if it works like this in pva then it will work in gel too... it also depends on the grade of pva you are using, also to get a good attachment to glass use a 1% pva with very little dichromate to coat the glass then let it dry in the sun
http://www.signindustry.com/screen/arti ... lsion.php3


vasimv
Posts: 58
Joined: Tue Apr 23, 2019 2:16 am

Re: D.I.Y. holographic photopolymer

Post by vasimv » Sat Aug 24, 2019 3:38 pm

dannybee wrote:
Sat Aug 24, 2019 12:41 pm
I have worked with pva in both silver and dichromate , its sounds like the speed ball (DIAZO sensitizer) is acting like a crosslinker, I've wanted to try this too, if it is a crosslinker in your pva you should see a weak image shortly after exposer with no processing (just like dcgpva) you could also include a dye with a electronic doner (tea) , then use fix just as in dcg and process just like a dcg. and if it works like this in pva then it will work in gel too...
If i remember correctly, reflection images appears only after water bath, i guess it does like photoresists that used for PCBs making. I don't see a way to process it is like DCG, exposed layer seems to be fully water resistant. I'll try to do some experiments with dye later, thanks for idea.
dannybee wrote:
Sat Aug 24, 2019 12:41 pm
it also depends on the grade of pva you are using, also to get a good attachment to glass use a 1% pva with very little dichromate to coat the glass then let it dry in the sun
http://www.signindustry.com/screen/arti ... lsion.php3
Well, i had no problem with attaching it to glass, just poured some and used mayer bar. Biggest problem is the emulsion solution is low viscosity and needed to be dryed at very good levelled surface to get uniform thickness.

dannybee
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Re: D.I.Y. holographic photopolymer

Post by dannybee » Tue Aug 27, 2019 8:48 pm

just a thought here could be that you have too much sensitizer in the mix, try backing it down until it doesn't crosslink every thing :D

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