making an IR photo filter

[nytecam]

Recently I posted shots on DIY Observatory using an IR-transmitting filter [iRtf] via my Archos 7" Cobalt tablet the shows the typical "white foliage and black skies" of IR photography.  Virtually any digital camera should work with a 'black' IR-tf over the lens.  I used  a Cokin resin filter A.007 [=Kodak 89B].  The filter blocks a lot of light so upping the ISO rating helps.  The images appear pink on the LCD display and as captured to disk - I usually grey-scale them before posting but whatever suit you is ok.

You can make an IRtf with a pair of crossed pola filters than 'appear' to block the light eg black or a pair of complementary [opposite colour] acetate gels as used in theatre spotlights - all these gels transmit IR or else the lamp would catch fire!  Suggest deep green + red paired gels as IRtf but try others in combination that appear 'black'.   A folded pair of red/green 3D cardboard glasses also work ok for IRtf.  Good luck;-)

Beware -  these pro or DIY filters appear black but transmit IR virtually unimpeded - don't hold them to the eye to view the sun or bright lamps as eye damage may result !

Nytecam

[Norman Copeland]

Sounds like before computers you would of been experimenting with silver and phosphate for dexterity, it's been 30 years since I've developed on paper and I'm just wondering if it would at some stage be worth going back and experimenting. The history of using silver is an interesting observation.

[nytecam]

Sounds like before computers you would of been experimenting with silver and phosphate for dexterity, it's been 30 years since I've developed on paper and I'm just wondering if it would at some stage be worth going back and experimenting. The history of using silver is an interesting observation.

Norman - as you probably know Kodak marketed IR B&W and IR-Ektachrome though I never used the IR version of the latter :-)