3. The warm colors are at the top of the horizontal
axis. The cool colors are at the bottom.
Table 3-5.–Neutral Density Filters
4. Filters of the same color are added and
subtracted normally:
30M + 20M= 50M
10B - 05B = 05B
5.When two filters of different colors and equal
densities are combined, the color of the combined filters
changes, but the peak density remains the same.
10M + 10C = 10B
10R + 10G = 10Y
6. A filter combination having all three primary
colors creates neutral density. To correct this neutral
density, subtract the lowest density from each color.
10R + 20G + 30B
Density
.10
.20
.30
.40
.50
.60
.70
.80
.90
1.00
-10
-10
-10
0R + 10C + 20B (Results)
amount of exposure reduction provided, are shown in
table 3-5.
SPECIAL-PURPOSE FILTERS
Special-purpose filters for use with black-and-white
film are those filters not classified specifically as
contrast or correction filters. Some of the special-
purpose filters can be used with both black-and-white
and color film. Two of these special-purpose filters are
intended primarily for use with color film.
When you desire to reduce the depth of field but
maintain a given shutter speed, ND filters permit the use
of a larger f/stop which in turn, reduces the depth of
field. Neutral density filters are used extensively in
motion-picture photography where depth of field is
usually quite deep. ND filters are also used with mirror
type of lenses where there is no aperture control.
NEUTRAL DENSITY FILTERS
HAZE FILTERS
Neutral density (ND) filters reduce the amount of
light passing through a camera lens without changing
the reproduction of colors in the scene. These filters are
nonselective in their absorption of colors of light and
therefore uniformly reduce the various colors of light in
the spectrum. Thus white light and colored light are
transmitted through an ND filter with only the intensity
of the light being affected. These filters can be used with
both black-and-white and color film. Neutral density
filters are gray in appearance. These filters may be
needed for pictures being made of a brilliant subject in
bright sunlight. When you have set the fastest shutter
speed and the smallest f/stop and still cannot make the
picture without overexposing the film, you can use an
ND filter to further reduce the exposure. Neutral density
filters manufactured by Kodak are called Wratten
Neutral Density Filters and are available in several
densities. The ten most popular densities, with the
Suspended in the earth's atmosphere are minute
particles of vapor and dust that cause a veil-like
appearance called haze. This haze is most apparent in
distant scenes. Haze is the result of sunlight being
scattered by minute particles of matter that are present
in the air. The amount of haze can vary due to
atmospheric conditions. Haze should not be confused
with mist, fog, smog, smoke, or clouds. These con-
ditions can also produce a veil-like appearance, but
filters have no effect.
When sunlight is scattered, both green light and red
light are also scattered by the ever-present haze, but not
nearly as much as ultraviolet radiation, violet, and blue
light.
When filters are used to absorb scattered sunlight,
penetration of the haze is possible. A haze filter is any
filter that absorbs atmospherically scattered sunlight. A
Exposure reduced
by f/stops
1/3
2/3
1
1 1/3
12/3
2
2 1/3
2 2/3
3
3 1/3
3-7
