Search found 793 matches

by Joe Farina
Tue Mar 19, 2024 1:30 pm
Forum: General Holography
Topic: beam ratios: silver vs. polymer vs. DCG
Replies: 5
Views: 194

Re: beam ratios: silver vs. polymer vs. DCG

Wow, thank you Din and Joy! Joy's comments seem to confirm my impressions about Bayfol HX200 photopolymer. When I did the first two, they were just simple Denisyuk with no extra object light. I didn't measure the reference/object ratio, but the reference must have been much, much stronger. White obj...
by Joe Farina
Mon Mar 18, 2024 10:25 am
Forum: General Holography
Topic: beam ratios: silver vs. polymer vs. DCG
Replies: 5
Views: 194

Re: beam ratios: silver vs. polymer vs. DCG

The Bayfol material is impressive, and it works reasonably well with a very high reference to object ratio. But, compared to (non-dye) DCG, it doesn't seem capable of very high brightness, without a certain quantity of object light. In my limited experience, that is. I did a hologram yesterday with ...
by Joe Farina
Mon Mar 18, 2024 9:37 am
Forum: General Holography
Topic: beam ratios: silver vs. polymer vs. DCG
Replies: 5
Views: 194

beam ratios: silver vs. polymer vs. DCG

Having done my first few photopolymer holograms (Bayfol HX200), it seems that polymer is more dependent on beam ratio equality (ideally ~1:1 for a reflection hologram) compared to DCG. It reminds me of silver halide, but perhaps not as extreme. Maybe this is due to the dyes present in polymer and si...
by Joe Farina
Fri Feb 16, 2024 12:43 pm
Forum: For Sale / Want to Buy / Trade
Topic: Looking for photopolymer films
Replies: 11
Views: 10619

Re: Looking for photopolymer films

Like Bob said previously, the films have a stickiness comparable to a post-it note. First remove the PE protective film by sticking a piece of adhesive tape to the corner, and peel it away. Then laminate it to your glass (a rubber roller is good for this). Bubbles and dust can be a problem at this s...
by Joe Farina
Tue Jan 30, 2024 12:15 pm
Forum: For Sale / Want to Buy / Trade
Topic: Looking for photopolymer films
Replies: 11
Views: 10619

Re: Looking for photopolymer films

Regarding availability, I ordered from Geola in Lithuania recently with no problems. They are professional and fast.

https://www.geola.com/product/photopolymer/

The total cost including shipping to the US was 149 Euros for 36 sheets of HX200 (2 packs of 18 each) of the 10cm X 10cm size.
by Joe Farina
Thu Jan 25, 2024 9:44 am
Forum: For Sale / Want to Buy / Trade
Topic: Manual for the Coherent Sapphire 532-300
Replies: 7
Views: 1062

Re: Manual for the Coherent Sapphire 532-300

What I tried to convey with "reasonably" collimated (a poor choice of words, I admit) was that it's not wildly diverging coming out of the aperture (and that it could be "tamed" with lenses).
by Joe Farina
Thu Jan 25, 2024 6:56 am
Forum: For Sale / Want to Buy / Trade
Topic: Manual for the Coherent Sapphire 532-300
Replies: 7
Views: 1062

Re: Manual for the Coherent Sapphire 532-300

Hi Andrei, Thanks for the tip about the Michelson! Sounds like a very good idea. That's fascinating that a ring cavity (Coherent 532) has mode hops. I think that for many types of lasers, this is something that can be accepted and dealt with. I could be mistaken, but I thought FPT FT means fiber-cou...
by Joe Farina
Wed Jan 24, 2024 2:03 pm
Forum: For Sale / Want to Buy / Trade
Topic: Manual for the Coherent Sapphire 532-300
Replies: 7
Views: 1062

Re: Manual for the Coherent Sapphire 532-300

I can't help with the manual, but I recently bought a similar Sapphire 532-300 (formerly fiber-coupled) from Dave on Facebook. Dave said it worked for holograms, and that was good enough for me. I haven't tried it yet. By the way, my Sapphire 488-200 does appear to mode-hop once in a while (at certa...
by Joe Farina
Tue Jan 23, 2024 10:44 am
Forum: For Sale / Want to Buy / Trade
Topic: Donate and Help Conservation Research?
Replies: 14
Views: 2232

Re: Donate and Help Conservation Research?

Thanks, Din, this paper is new to me, and I appreciate it. The paper is disappointing, because it's more of a "survey" of art, rather than a technical study. It did have an interesting list of potential problems with silver halide materials. I think this might be useful for the original po...
by Joe Farina
Mon Jan 22, 2024 9:47 am
Forum: For Sale / Want to Buy / Trade
Topic: Donate and Help Conservation Research?
Replies: 14
Views: 2232

Re: Donate and Help Conservation Research?

Hi, I think this would be a very interesting area of research. As far as I know, there has never been an independent and unbiased evaluation of the permanence or longevity of holograms. Holograms vary enormously in terms of recording material, processing regime, sealing or mounting technique, and ty...