Color and Calibration
- Additive Color
- The additive primary colors are red, green and blue. These
additive primaries represent the three main components of white
light. Used individually or together, these three colors of light
can be mixed to create nearly all colors. Additive color is used
in scanners and computer displays.
- The act of adjusting equipment so that it performs in
accordance with an established standard. Calibration is necessary
when equipment is installed and continues to be a necessary part
of on-going use and maintenance.
- CIE LAB
- A device independent color space that can be used to describe
the entire visual spectrum. This color space is being used in
modern color management software to facilitate conversion of data
from a scanner to a display, or from a display to an output
- Closed Loop Calibration
- A method of scanner calibration where a factory provided file
is printed on the desired printer and then scanned back in. The
scanned result is compared with the original file data and a
compensation setting is stored. This compensation setting is used
as a filter for all future scans to be output on that particular
- The process printing colors. Cyan, Magenta, Yellow, Black.
- Color Management System
- Abbreviated CMS. A CMS is a set of software designed to
increase the accuracy and consistency of color between a scanner,
display and printer. A CMS consists of: "Device profiles" which
document the performance of the particular scanner, display and
printer you may own. A "device transformation engine" that coverts
data between the scanner, display and printer. A "gamut
compensation mechanism" that addresses differences between the
capabilities of the scanner, display and printer. And a "device
independent color space" through which all color transformations
- Color Space
- A color space is a particular language used to describe color.
Examples of color spaces are: RGB, CMYK, HSB, CIE LAB.
- Device Dependent Color Space
- For example RGB. A device dependent color space is one in
which the same color values will give different results on
different devices. This is why the same scan file will appear
different when viewed on different computer displays.
- Device Independent Color Space
- For example CIE LAB. A device independent color space is one
in which a particular color value is considered absolute and not
subject to interpretation. CIE LAB is the central color space in
color management systems and is used to translate between
different device dependent color spaces such as scanner RGB and
- Device Profile
- A file used as part of a Color Management System. A device
profile contains information documenting the unique
characteristics of that brand and model of device. There are
device profiles for scanners, computer displays and printers
- Gamma Adjustment
- An adjustment that makes the Tonal Distribution lighter or
darker. A Gamma Adjustment may be made to a monitor, a scanner or
to an image during the scanning or image editing process.
- A term referring to the range of available color on a display
or printer. A particular color is either in or out of the gamut of
the device. If outside, it cannot be accurately shown on that
display or printed on that output device. (Each device has its own
- Gamut Alarm
- A software function that tells the user if a color falls
outside the Gamut of the currently targeted printer.
- Gamut Transformation
- A function of Color Management Systems where out of Gamut
colors are converted to colors within the Gamut of the targeted
printer. For photographs, the gamut transformation progressively
transforms all color in the image so the image retains a realistic
appearance. For line-art, only the colors falling out of gamut are
changed and the rest of the art is left intact.
- A color space with the three variable of Hue. Lightness.
Saturation. See HSB.
- A color space with the three variables of Hue. Saturation.
Brightness. Hue means color (as in the color wheel.) Saturation is
an indication relating to the richness or vibrancy of the color.
Brightness is a term best related to the intensity of light
illuminating the object.
- Lightness is a term referring to the lightness or brightness
of an image. Also, as part of the HSL color space, it refers to
the imagined amount of light illuminating a viewed color.
- Output Simulation
- A term used in some Color Management Systems to describe the
function whereby the computer display is used to predict the
results achievable on a particular printer.
- The CIE based device independent color space used to store
images on a Kodak PhotoCD disc.
- Red, Green, Blue. These Additive Primary colors are the basic
elements of white light. By mixing them in a computer monitor or
in a scanned image file, other colors can be made. For instance,
Red and Green light make Yellow light. and equal amounts of all
three make grey.
- Saturation is one attribute of color in the color space called
HSB. (Hue Saturation, Brightness) Saturation is a characteristic
indicating the vibrancy or intensity of a hue. A color with high
saturation will appear more intense than the same color with less.
- Subtractive Color
- A term used to describe the subtractive primary colors: Cyan,
magenta, yellow. As ink applied to a piece of paper by a printing
press, these colors absorb light and alter the colors seen by one
looking at the press sheet. Cyan ink absorbs the red third of the
spectrum, magenta ink absorbs the green third, and yellow ink
absorbs the blue third. This should theoretically cause the viewer
to see a black color, (with three thirds absorbed, no light is
reflected) but due to unavoidable impurities in the inks, there is
still light reflected and the viewer sees a muddy brown.
- Tonal Distribution
- Tonal Distribution describes the distribution of various
bright or dark tones within an image. During the scanning or image
editing stage, tones can be redistributed lightening a dark image
or darkening a light one.
- Viewing Conditions
- A term used to describe the lighting conditions surrounding a
computer display or color proof viewing area. The intensity and
type of light have a dramatic impact on the colors perceived by