204 Glossary
Bracketing Time-honored photo technique where multiple
images of the same subject are made at different exposure levels.
The idea is that one of them will be the best and some may be
acceptable. In Auto Bracket mode, the fi rst frame is exposed
with no compensation, the second is underexposed, and the third
is overexposed. Depending on the type of camera you have, this
order may differ, or may even be programmable.
Byte Each electronic signal is 1 bit. To represent more-complex
numbers or images, computers combine these signals into larger
8-bit groups called bytes.
CCD Charge-coupled device. This is the kind of light- gathering
device used in scanners, digital cameras, and camcorders to
convert the light passing through a lens into the electronic equiv-
alent of your original image.
CD-R CD Recordable. With these discs, you can write image-
fi le data only once and read it many times.
CD-ROM CD read-only memory. A disc that resembles a
music compact disc, but can hold all kinds of digital information,
including photographs.
CD-RW CD ReWritable. You can write and read these discs
many times, but the discs themselves cost more than CD-Rs.
CIELAB Color system created by the Committee Internatio-
nale d’Eclairage to produce a color space consisting of all visible
colors. The CIELAB system, sometimes shortened to just LAB,
forms the basis for most contemporary color-matching systems
and lets you convert, for example, RGB images to LAB or
CMYK to produce accurate color matching.
Clipping Loss of image information in a region of a photo-
graph that is brighter than the imaging device can handle or that
is outside the color gamut of the space used to represent the
photograph.
CMOS Complementary metal-oxide semiconductor. An alter-
native to the CCD (charge-coupled device) imaging chips used
by some digital cameras. The CMOS chip is simpler to
manufacture, so it costs less. It also uses less power than CCD
chips do, so it doesn’t drain batteries as fast. The downside is
that the chip does not perform as well as CCD imagers under
low-light conditions, but recent digital SLR models are said to
have improved performance under less-than-ideal lighting
conditions.
CMS Color-management system. Software that helps produce
an accurate reproduction of your original color photograph. A
good CMS includes calibration and characterization aspects and
is (mostly) software based. CMS is used to match the color that