first column lighten colors next to them, and opposite
filters darken colors on the print. For example, a yellow-
green No. 11 filter lightens subjects that are yellow-green
or yellow and darkens subjects that are violet. A No. 44
cyan filter lightens blue and blue-green and darkens light
red and orange.
USING FILTERS IN BLACK-AND-WHITE
Filters may be used in black and white photography
for the following major reasons:
To make the tones of gray in the final product
conform more closely to the visual effects of
colors in the original scene.
To provide scenic contrast, such as darkening the
sky so that clouds stand out. You can use a
No. 15 or a No. 25 filter for this purpose.
To lighten or darken a color to make it
disappear or stand out in sharp contrast. An
example of this could be photographing an old
document that is written in blue ink and has
yellowed with age. Here, a deep yellow filter
would darken the blue writing, and at the same
time, lighten and possibly remove the yellow
Whenever you use a filter, you must change the
exposure. The amount of change depends on the
sensitivity of the film to the colors absorbed by the filter
as well as the quantity of that color in the type of light
used. The effects of the filter in terms of exposure
correction are given on the film data sheet as a filter
The filter factor may be applied to the exposure by
opening the diagram one f/stop each time the filter factor
is doubled. Thus a factor of two requires that the diagram
be opened one f/stop larger than is needed for correct
exposure without a filter; a factor of four call for two
f/stops, a factor of eight for three f/stops, and so on.
An easy formula for determining exposure correction
when you are using a filter is to divide the film speed by
the filter factor and use the results as a corrected film
speed on your exposure meter. As an example, when you
use a black-and-white film with an ISO of 400 and a No.
11 filter (filter factor four), divide four into 400 and use
the results, 100, as the film speed on the exposure meter.
When using this method, make sure you return the meter
dial to the correct film speed after using the filter.
FILTER FOR COLOR PHOTOGRAPHY
Problems associated with color materials are quite
different from those encountered with black-and-white
materials. In color photography, the main problem is
achieving correct color balance. The principal factor
involved is the color temperature of the light source being
used to illuminate the subject. This provides a natural
appearance to the final product. Filters for color
photography are classified as light balancing, conversion,
and color compensating.
Light Balancing Filters
Light balancing filters come in two series (not to be
confused with a series that indicated physical size): the
series 81 (yellowish filters) are used to lower the color
temperature of light source, and the series 82 (bluish
filters) are used to raised the color temperature of light
from a light source. Both series are used when a tungsten
light source is used with color film.
Conversion filters are used in color photography
when a significant adjustment of an exposing light is
required to convert the color quality of the exposing light
the color temperature for which a film is balanced.
Conversion filters generally come in two series. The
80 series of filters are blue in color and convert tungsten
light to color qualities acceptable for use with daylight
film. The 85 series are amber in color and convert
daylight to color qualities acceptable for use with tungsten
The correct filter to use for a given situation with a
given film can be determined by reading filter and film
data sheets. If your are in doubt, seek help from your ship
or base imaging facility.
Color Compensating Filters
Color compensating (CC) filters are used to adjust
the overall color balance obtained from color film,
particularly slide film. Without the use of color
compensating filters, improper color cast can result.
For cameras, CC filters are normally used to color
balance the light from sources, such as fluorescent,
tungsten, and mercury-vapor lights, and the bounce light
reflected from colored surfaces. They are also used to
balance lighting effects under unusual circumstances (such
as underwater lighting). These filters can be used