Black & White IR film is hard to use properly in the field. The effect desired in using this film is the ability to take a picture of something in total darkness except for some type of IR source.
The camera light meter doesn't measure IR nor do most handheld meters. Exposure is a guess after much testing with your camera, lens and light source.
The film is considered professional and so should be stored frozen. Thaw 4 hours before exposure and developed immediately for best results. This can make the film brittle and have static. Static can expose the film inside the camera, fogging it. The film must remain inside its protective canister and out of bright light. You should also protect the back of your camera from bright light sources when IR film is loaded.
Visible light lenses (those are what are typically found on cameras using film) do not focus IR at the same point on the film plane as they do visible light (ROYGBIV). A slight correction needs to be made for it. Most manual focus quality lenses have two marks on the focus barrel. Usually the red one is for IR. You focus the lens, then look at the barrel and switch the focused spot to the red mark.
IR film is sensitive to visible light as well as IR and so to get the best use out of the film an 87-wratten filter should be used on the lens. Unfortunately you can not see through this filter so you need to remove it for focus and then attach it for exposure. Another way of using it properly would be to have a very powerful flash head with an 87 filter completely covering it.
Focus at night is difficult if you can't see. Autofocus cameras should not be used with IR film. You must work out the hyperfocal setting for the camera and lens your using.
Processing the film is more stringent then with regular panchromatic B&W films. What you may have thought was a good process of agitation during development may only create air bells, bromide stain and surge marks, etc. The film base is different than regular film base. It is on acetate. Very hard to cut but scratches, bends and kinks quite easily.
IR reflectance off of common objects is unpredictable in effect. I have seen plenty of strange images made with the stuff in my cameras. I usually hope that out of a roll of film (12-20 exposures) and with 2-3 subjects, I get at least one picture worth printing for each subject.
I think that a lot of people who find mysterious things in these pictures that were not there when the picture was taken are seeing chemical stains from fingers, double exposures, film imperfections, X-ray fogging or are very creative in connecting the dots.
Posted on Nov 6, 2002, 4:17 PM from IP address 12.230.53.185