Tiffen Filter Grades, Camera Filters for Both Color and BLACK-AND-WHITE, Ultraviolet Filters

difference in the readings is the compensation needed for that filter. You could also use a spot meter, reading the same bright patch, with similar results. There are some exceptions to this depending on the filter color, the meter sensitivity, and the target color, but this is often better than taking a guess.

Filter Grades

Many filter types are available in a range of "grades" of differing strengths. This allows the extent of the effect to be tailored to suit various situations. The grade numbering range can vary with the effect type, and generally, the higher the number, the stronger the effect. Unless otherwise stated, there is no mathematical relationship between the numbers and the strengths. A grade 4 is not twice the strength of a grade 2. A grade 1 plus a grade 4 doesn't add up to a grade 5.

CAMERA FILTERS FOR BOTH COLOR AND BLACK-AND-WHITE

Ultraviolet Filters

Film, as well as video, often exhibits a greater sensitivity to what is to us invisible, ultraviolet light. This is most often outdoors, especially at high altitudes, where the UV- absorbing atmosphere is thinner; and over long distances, such as marine scenes. It can show up as a bluish color cast with color film, or it can cause a low-contrast haze that diminishes details, especially when viewing far-away objects, in either color or black-and- white. Ultraviolet filters absorb UV light generally without affecting light in the visible region.

It is important to distinguish between UV-generated haze and that of air-borne particles, such as smog. The latter is made up of opaque matter that absorbs visible light as well as UV, and will not be appreciably removed by a UV filter.

Ultraviolet filters come in a variety of absorption levels, usually measured by their percent transmission at 400 nanometers (nm), the visible-UV wavelength boundary. Use a filter that transmits zero percent at 400 nm, such as the Tiffen Haze 2, for aerial and far- distant scenes; the Tiffen Haze 1, transmitting 29% at 400 nm, is fine for average situations.

Infra-Red Filters

Certain special situations call for the use of black-and-white or color infra-red sensitive films. For aerial haze penetration, recording heat effects, and other purposes they are invaluable. Their color and tonal renditions are very different, however, from other film types (consult film manufacturers for further details). Various filters are used to reduce unwanted visible light. Red, orange, and yellow filters, as used for panchromatic black-and- white film can enhance contrast and alter color. Total visible light absorption transmitting only infra-red, as with the Wratten #87 or #89 series of filters, can also be useful. The results will vary with film type and other factors. Prior testing for most situations is a must.

Neutral Density Filters

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CAMERA FILTERS © Ira Tiffen