Although we cannot see this light, it is reactive with photographic materials. Therefore, it is possible to produce images that may only be observed using photography. Extending just beyond the visible region in the other direction from 700 nm and higher is the infrared region of light radiation. The range of infrared light close to the visible spectrum is also photographically reactive. Film has varying degrees of sensitivity to the amount and intensity of light.
Faster film reacts quicker to light, therefore it requires less light for proper exposure.
The drawback of using higher ASA film is that enlarged photos may appear grainy and less detailed. Latitude in photography is the ability to produce a good picture from a negative that is slightly underexposed or slightly overexposed. These corrections can be to print film through adjustments in the print processing. Slide film is not designed for print processing and thus lacks latitude. This means that the exposure must be exact for the photo to turn out correctly.