mounting gelatine filters between glass

[Drew Wiley]

Absurd, Havoc. Polyester costs around $4 to $12 apiece for 3x3 inch, for example, but new gels $30 up to $75 or so, depending. I think you're confusing these with thicker acrylic resin filters, similar to colored plexiglas, which are optically very clear, but scratch easily and are prone to reflections.
Sometimes "new old stock" gel filters show up inexpensively on EBay simply because they've been gathering dust on some dealers back room shelf for three decades, and they simply want to get rid of them. A discounter who has quite a selection of new old filters is filterfind.net.
But the problem in this case is finding filter sizes large enough for a tricolor sheet film camera. Large gel sheets are quite expensive, but easy to cut down.

[Maris Rusis]

I've used Wratten gelatin filters in scientific applications, not photography, and I found those filters are so thin that they have a negligible effect on image quality even if they are not dead flat, even if they are tilted a bit. Maybe they don't need mounting between glass, just get them into cardboard frames, and fix them into the light path somehow?

[Drew Wiley]

Maris, I think the problem with that would be their fragility and how to keep them free of dust. A tricolor sheet film camera means not only three sheets of film per shot which must be clean, but three potentially electrostatic filters. But I have seen an old tricolor camera made that way; the insides sure didn't look pretty.
Fussier still would be simply placing a thin gel directly over the sheet film in the holder itself, but it's a hypothetical option, and no doubt somebody has tried it.
If I had a ton of money to waste and an elephant and mahout to carry my gear, it would be fun to order up a custom beamsplitter prism tricolor camera, analogous to a Technicolor movie camera, but matched to single-shot sheet film.

[Havoc]

Absurd, Havoc. Polyester costs around $4 to $12 apiece for 3x3 inch, for example, but new gels $30 up to $75 or so, depending. I think you're confusing these with thicker acrylic resin filters, similar to colored plexiglas, which are optically very clear, but scratch easily and are prone to reflections.

Drew, I bought a set of Lee "polyester technical filter" (R, G, B) 100x100 and that was 36 euro/piece. The gelatine filters are made by a german company that casts their own sheets and they quoted 26 euro/piece for 82x107.5. I haven't seen a piece yet, so I'm not naming them now. When I get them and have seen them I'll post the address. But they

Please don't confuse european prices and US prices, they have very little in common.

[Drew Wiley]

That's interesting. Thank you. I wasn't even aware of a German company making gels. Do they use the same Wratten numbering system?

[Havoc]

They use an internal numbering (unless that is the Agfa numbering) but can provide according to Agfa or Kodak numbering. Or to specification. Also neutral density (including center filters for wides), IR, pola (linear and circular), for darkroom lamps (even colored lamps are possible) etc. Maximum size is 300x300 (mm).

From their docs I see they have 9 sets of tricolor filters.

[Tin Can]

Please post your source when you are done vetting

Thank you

They use an internal numbering (unless that is the Agfa numbering) but can provide according to Agfa or Kodak numbering. Or to specification. Also neutral density (including center filters for wides), IR, pola (linear and circular), for darkroom lamps (even colored lamps are possible) etc. Maximum size is 300x300 (mm).

From their docs I see they have 9 sets of tricolor filters.