LCD Screen Protectors for Photopolymer

Holography related topics.
Nnnn
Posts: 39
Joined: Tue Nov 06, 2018 3:23 am

LCD Screen Protectors for Photopolymer

Post by Nnnn »

Following in BobH's footsteps, I would like to share my method for laminating photopolymer holograms.

When making test holograms with Liti's photopolymer that comes pre-mounted on glass, I found that it was very hard to store finished holograms safely without attracting scratches and dust. And worse, a lot of them would start peeling off of the glass, getting dust to the emulsion's surface. So I started trying out a number of laminates available at local stores, but all of them would ruin the image and shift the colors. (Red -> Green, Green -> Blue).

I skimmed through Practical Holography 5th Ed. again looking for solutions and found the following: (p. 324, "Preserving the Color in Color Holograms"):
Once you have exposed and processed your hologram, seal it against the ingress of any moisture. Laminate films to plastic or glass, emulsion down. Note that certain laminating materials may bond with gelatin or photopolymer and may change the color balance, and at worst even destroy your holographic image. [...] For silver halide film, Geola recommends 3 M 9483 optically clear laminate adhesive or similar products.
I had a look and it seemed like 3M's 9483 laminate had to be custom ordered, so I never got around to trying it out. But one day, I was at a dollar store in Japan and found these cheap 5.2"/5.5" glass lcd screen protectors meant for smartphones, and I thought that's it! So I tried it out immediately.
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I simply sandwich the exposed photopolymer between two glass screen protectors of the same size. It looks like the laminate used is non-abrasive, since I don't see any color shifting, and because it's glass the image is nice and clear.

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Nnnn
Posts: 39
Joined: Tue Nov 06, 2018 3:23 am

Re: LCD Screen Protectors for Photopolymer

Post by Nnnn »

I like this technique for a few reasons, so I'd like to list a few pros and cons I've found:

Pros:
1) It protects the emulsion, but it also protects the front of the polymer from scratches and dust. It's very nice being able to store test holograms and take them out and touch them without worrying about ruining the actual film.
2) It's thin and lightweight. It's a lot easier to store than thicker glass because it takes not nearly as much room.
3) It's cheap, and doesn't need any special equipment. Since this can be done by hand and these glass protectors are readily found for <$1.00 each, I think maybe this would be good for beginners who want to keep smaller test holos safe.
4) No glass cutting required.
5) Because the glass comes individually packaged and with protecting film, each glass is perfectly clean from the start. (You don't need to clean the glass beforehand!)
6) The glass edges are rounded!
7) It's not permanent, so if the glass cracks it can be replaced with a similar piece. But even if it does crack, it won't shatter or break in half.

Cons:
1) The sizes are fixed, so unless you plan on cutting the glass, you'd have to match your holos to the glass size instead of the other way around. Most sizes are around 5" for android/iphone, but they also sell tablet size glass screen protectors too.
2) If the glass is larger than the holo, then gaps of air can form in the part where the two protectors are touching with no holo.
3) The glass is very thin, so it is not suitable for shooting unexposed film. I've tried this a few times, and I've gotten black splotches on the hologram.
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Nnnn
Posts: 39
Joined: Tue Nov 06, 2018 3:23 am

Re: LCD Screen Protectors for Photopolymer

Post by Nnnn »

There's still a lot of things I'm unsure about, and a lot of things I want to try. So I'd like to hear peoples' opinions on this material!

1) Is there any way I could try and stress test this to make sure it's keeping the emulsion safe? Maybe soaking the entire sandwich in 100% alcohol for a day or two and see if anything changes?
2) Maybe using a pouch laminator like BobH posted could help with getting cleaner laminations onto the glass?
3) Would this be suitable for DCG I wonder? What about silver halide film?
4) (Suggestion from holomaker:) Do regular glass cutters work on this material?
5) Are certain brands/materials better than others? Some of them have blue-light cut properties (~405nm), anti-glare/anti-scratch coatings, etc. I imagine some of these may help/hurt the playback image.

And, here's another hologram for good measure -- a two-color test holo. No color shifting!
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holomaker
Posts: 772
Joined: Wed Jan 07, 2015 8:01 am

Re: LCD Screen Protectors for Photopolymer

Post by holomaker »

Fantastic, I’ve already ordered a couple of protectors to give it a try .. and nice job on the two color hologram !
kgyozo
Posts: 1
Joined: Thu Aug 13, 2020 10:49 am

Re: LCD Screen Protectors for Photopolymer

Post by kgyozo »

Hi,

Do you sandwich the emulsion with the glass plate it comes premounted on, or do you separate the emulsion from the glass plate, and put only that between a pair of tempered screen protector glass?
Din
Posts: 402
Joined: Thu Mar 12, 2015 4:47 pm

Re: LCD Screen Protectors for Photopolymer

Post by Din »

Nnnn wrote: Wed Jan 20, 2021 3:04 am There's still a lot of things I'm unsure about, and a lot of things I want to try. So I'd like to hear peoples' opinions on this material!

1) Is there any way I could try and stress test this to make sure it's keeping the emulsion safe? Maybe soaking the entire sandwich in 100% alcohol for a day or two and see if anything changes?
There's a possibility that the material is birefringent. if so, placing it between crossed polarisers would show interference lines. If you set up such a system and tested at regular intervals, you can see if the interference lines are stable. if so, there's no change, if not, stresses are being applied.
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