Light temperature becomes critical when reproducing color images and an
imbalance light source will skew tonal values in black-and-white
reproduction. The most common lamps in Navy Graphics shops are the
tungsten lamp, fluorescent lamp, and quartz iodine lamp variations.
TUNGSTEN LAMPS: Tungsten lamps are excellent for use in black-and-
white reproduction. Tungsten lamps are available as 3200 degrees Kelvin
(K) and 3400 degrees Kelvin. Lamps rated 3400 degrees K are used less
because they have a short life of 4 to 6 hours.
FLUORESCENT LAMPS: Use fluorescent lamps when the original has a
textured or uneven surface and little reduction or enlargement. Even
illumination of a smooth-surfaced original is difficult to obtain. When you
use fluorescent lamps, arrange the tubes in a square pattern parallel to the
edges of the copyboard.
QUARTZ IODINE LAMPS: Quartz iodine lamps produce a very intense
light particularly suited to general copy work. They maintain a fairly
constant color temperature throughout their life.
Reflectors evenly distribute light over the surface of an original, eliminating
hot spots. Reflectors also funnel more light toward the original that shortens
exposure times. Certain types of lights have built-in reflectors. When you
use a lamp with a built-in reflector, also use a lens hood to shade the lens
from glare and stray light.
Keep all lamps clean and free of dust and finger smudges. Handle lamps
carefully. Replace all lamps in the system simultaneously. As lamps age,
temperature variations occur. Failure to replace all lamps creates an
imbalance in temperature and intensity of illumination.
Continued on next page