I really need help even though I’ve been researching this for a while. I want to build a FTIR setup using a homemade projector. My questions are would frosted acrylic work as a diffuser, and if not would tissue paper work? Also, for the projection surface I want to use Rosco Grey but I have heard that this sometimes diminishes the blobs, is that true? Also where could I order Rosco from? And for the silicone layer would spray on silicone like the stuff in the links below work?

And finally, does this setup work:

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Rosco
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Frosted Acrylic/Tissue Paper
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Silicone
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Acrylic
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http://www.estreetplastics.com/
http://www.valvoline.com/pages/products/product_detail.asp?product=36

If you used frosted acrylic I think that would kill your projection.  Rosco works as a diffuser, it just absorbs a lot of IR Light.

So can you explain what the best way to do this is please. This is all the answers I get, these small tidbits that contradict each other. Please just a definitive answer. Thank you.

Well, I am not much of an FTIR person, but from what I understand:

Rosco
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SIlicone
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Acrylic