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Geola question

Posted: Thu Jun 11, 2020 9:33 am
by Wackhaus
Hi, so I believe it was last summer, that geola had an artist at the Holocenter exhibit, with a technology I hadn't seen before that could be built with something like unity or 3d studio max if I recall, and then sent in for a print of that type to be made and mailed back to you.
Can someone forward me information on this again?
Thanks :)

Re: Geola question

Posted: Thu Jun 11, 2020 11:10 am
by Nnnn
Hey, I believe this is the service you're referring to:
https://geola.com/product/digital-holography-ilumogram/

Ultimate Holography is also doing something somewhat similar with their Chimera series.
https://www.ultimate-holography.com/chimera

Re: Geola question

Posted: Fri Jul 24, 2020 6:14 pm
by dannybee
Has anyone test this with the 640nm laser diode? What seem to be happening is the dye they use is for 632nm hene laser, and it blocks most of the 640nm light, so I thinking the 640nm is not good for geola polymer any ideas? It works find with a hene.any ideas would help

Re: Geola question

Posted: Fri Jul 24, 2020 8:21 pm
by jrburns47
Geola is selling Bayer/Covestro panchromatic HX200 photopolymer. Don’t know if they’re also selling some other photopolymer as well... if you’re referring to HX200, it’s definitely sensitive at 640nm. I’ll leave it to you to research online😊.

Re: Geola question

Posted: Sat Jul 25, 2020 11:40 am
by dannybee
according to the transmission of the polymer in 640nm is much less transmission than a hene, so that the problem with that 640nm it needs more light to go through the dye for a reflection, it would be ok for a transmission but a bit low for a reflection. if this is the same stuff as liti they probably have the red diode closer to the plate. but with hene it allows enough light to go through the polymer

Re: Geola question

Posted: Sat Jul 25, 2020 5:47 pm
by lobaz
One more thing to consider: photopolymer requires at least threshold irradiance [mW/cm2] in order to record anything. If yoour diode is weak, making the exposure longer does not help. (Contrary to silver halide, where you can usually compensate weak laser by longer exposure.) I did not test HX200 at 640 nm, but it should work.

Re: Geola question

Posted: Sun Jul 26, 2020 8:04 am
by Din
There are two ways of checking your theory that the dyes in the film are more absorptive at 640nm:

1. Record a grating on silver halide film with the diode. This will eliminate the laser itself.

2. Record a grating on silver halide, simultaneously behind a sheet of the polymer. But, be sure you use the same exposure you would have used on the silver halide alone. If you're right that the dyes are absorptive at 640nm, then insufficient light will get to the silver halide film behind the polymer, and the resulting hologram (on silver, remember) will be weak or non-existent.

Re: Geola question

Posted: Sun Jul 26, 2020 10:56 am
by dannybee
Thanks Dinesh you could also do this by measuring the intensity of the light going through and comparing it to the light coming in right?

Re: Geola question

Posted: Sun Jul 26, 2020 11:06 am
by dannybee
Thanks Dinesh you could also do this by measuring the intensity of the light going through and comparing it to the light coming in right? My hene is 18mw and my 640 diode is 25mw spread to about 5x7 at the plate film is a 4x4 .. this setup works fine with the hene & and the 532nm. ... a nice even spread of yellow , and like lobaz said maybe a 640nm and this amount of spread of red light is not meeting the required amount because of the transmission curve of this polymer ji

Re: Geola question

Posted: Sun Jul 26, 2020 11:08 am
by dannybee
Thanks Dinesh you could also do this by measuring the intensity of the light going through and comparing it to the light coming in right? My hene is 18mw and my 640 diode is 25mw spread to about 5x7 at the plate film is a 4x4 .. this setup works fine with the hene & and the 532nm. ... a nice even spread of yellow , and like lobaz said maybe a 640nm and this amount of spread of red light is not meeting the required amount because of the transmission curve of this polymer