Does anyone make UV/IR gelatin filters ?

[rafael_macia]

I would like to get a UV/IR GELATIN filter. Like a Kodak Wratten Filter 3x3 inch

Does anybody know if any manufacturer makes these?

The reason is; I want to put one, cut out to size, behind a 44mm screw in #13358 polarizer I have on a black 65 Elmar Viso lens.

44 is an oddball size Leitz produced for this lens (the silver Elmar is 41mm), and the polarizer is not threaded on the front.
So I am thinking a gel would be fine, positioned behind the small Series Six (of all sizes!) pol filter,

thanks

Rafael

[pgk]

You can try Lee filters www.leefilters.com - I couldn't see anything on their website but they are pretty comprehensive and you could always ask them. If they can't help I'm not sure who else can.

[Printmaker]

You might want to call BetterLight

Better Light, Inc.
1200 Industrial Road, #17
San Carlos, CA 94070-4129

Phone: 650-631-3680

or PhaseOne.

They both make 3 inch and 4 inch square filters. These filters do not look the same as the Leica filters but are designed to cut IR from sensors.

You might also want to try Dave at North Light:

North Light Products, Inc. - 2487 Spring St. Ste. 2
Redwood City, CA 94063 USA Tel. 650 366-5483

Dave has answers and sources for unusual filters.

[rafael_macia]

Thanks so much, for the tips.
I called Lee, and they make gelatin filters, but not UV/IR, they told me most likely it would have to be made from glass, something about Dichroic .......
But let me see.

I will keep checking



Rafael

[jaapv]

UV/IR filters are dichroic filters, that consist of ultrathin layers of coatings, that cut out a specific light frequency by interference.
To cut out a range of frequencies, like for instance IR light, dozens of such coatings must be applied, usually by evaporation.
That is only possible on very flat and stable surfaces. That means glass, not gelatin.
Gelatin filters are absorbtion filters, that are opaque to certain frequencies and block them that way. Something quite different.
An IR absorbing gelatin filter is impossible. IR light is high energy, the filter would have to be quite thick and would heat up and melt....

B&W filters are threaded female on the front and can be ordered in all thread sizes.

[adan]

Actually, IR light is low-energy compared to visible light. UV is the high-energy end of the visible spectrum, being about 10x as energetic as IR.

(UV is energetic enough to cause cell damage and skin cancer; IR is not. The EM spectrum in order of decreasing energy per photon is: Gamma rays, X-rays, UV, visible, IR, microwave, radio wave)

And there ARE absorption IR filters. But their effectiveness varies with their thickness (as all M8 owners know) and gelatin is just not thick enough to carry enough dye to be of use.