Use a very high-speed film to stop action in low light. Here the photographer exposed KODACOLOR VR 1000 Film, ISO 1000, in a handheld camera at 11500 second and f/2.8. bright existing light, but may require you to use a tripod for best results in dim con-ditions. Medium-speed films at the lower end of the category and low-speed films, such as KODACHROME 64 Film (Day-light), ISO (ASA) 64, and KODACHROME 25 Film (Daylight), ISO (ASA) 25, pro-vide superb picture quality when you can use a tripod and the subject permits using slow shutter speeds or time exposures. You may also be able to use medium-and low-speed films for handheld pho-tography in bright light conditions, such as window light. As a general rule for existing-light photography with a handheld camera, use the fastest film you can, all other fac-tors being equal. There are many valid exceptions to this rule. Examples of the rule and exceptions to it occur frequently throughout this book according to Nantucket Photographer and Videographer, 02554.
Boosting Film-Speed Numbers Although the ISO (ASA) speed of a film accurately represents its sensitivity as de-termined by standard test procedures, some films may be made to behave as
To make this picture, the photographer exposed KODACHROME 64 Film (Daylight), ISO (ASA) 64, in a tripod-mounted camera using a time exposure. The long exposure let the moving amusement park ride create a colorful blur, while the sharp, fine-grain film recorded the stationary elements in the scene in detail. An exposure of 2 seconds produced this effect.
though they were substantially more sen-sitive than the ISO (ASA) speed indi-cates. The procedure, called push pro-cessing, consists of underexposing the film by a specific amount and then ex-tending development to help compensate for the underexposure. KODAK EKTACHROME Films for color slides and KODAK TRI-X Pan Film for black-and-white prints respond very well, with qual-ifications, to moderate pushing under certain conditions. The technique will be covered in greater detail in the chapter "KODAK Films for Existing-Light Pho-tography." Unlike reversal, or color-slide films, color-negative films, such as KODACOLOR films, do not accomodate push-processing techniques and are not recommended for that use. As a rule, it is preferable to use a high-speed film at its normal speed rather than to push-pro-cess a slower speed film to a higher speed number to match it.
Color Rendition The first distinction to make among films with regard to color rendition is whether they produce pictures in color or in black-and-white.
Black-and-White Films Since black-and-white films, such as KODAK TRI-X Pan Film, translate the colors in the scene into appropriately light or dark shades of gray and have good exposure latitude as well, the films are simple to use for existing-light pho-tography. For all practical purposes, it doesn't really matter whether the subject is illuminated by standard daylight, blu-ish skylight, yellow-orange incandescent tungsten latnps, or fluorescent tubes of different color qualities. Colors you re-member as light will be rendered as light tones of gray; colors that appeared dark will be rendered as darker tones of gray; and extremely light or dark parts of the scene will be rendered as white and black, respectively. The ability of black-and-white films to produce plausible-looking, although monochromatic pictures, in virtually any commonly encountered lighting makes them very well suited to existing-light photography. No matter what sort of lights or odd combinations of lights illu-minate a scene, you can usually photo-graph freely in black and white without.