Archived posting to the Leica Users Group, 2002/10/03
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Thanks Nathan, Curiouser and curiouser! I can see I'll have to do a little homework before I get stuck into this IR stuff. It'll have to wait awhile until I finish other projects anyway. Can you recommend any good books on the subject, perhaps with good examples? - - PHC At 22:16 +0200, 3/10/02, Nathan Wajsman wrote: >Paul, > >IR film is sensitive to the full spectrum of visible light, not just infrared. The visible spectrum stops at somewhere around 700 nm. Ilford SFX and Konica IR are sensitive up to 750 nm, Maco 820 up to 820 nm (surprise) and Kodak HIE up to 900 nm. But in all cases the films are also sensitive to visible light, so you need to use an appropriate filter, otherwise the visible light will overwhelm the infrared. These filters cut out visible light wavelengths to varying degrees. The Heliopan filters are conveniently named, so that for example the 695 filter cuts out all light below 695 nm etc. > >Nathan - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html