User`s guide
49 | SPECTRAVIEW II - USER’S GUIDE
Color Separation – The separating of a color image into the cyan, magenta, yellow, and black
color layers used for printing.
Color Separation Tables – A set of conversion tables used to calculate the separating of RGB
images into the CMYK layers necessary for printing.
Color Space – A three dimensional representation of colors. Examples are RGB, CIE xyY, and
CIE Lab.
ColorSync – The Color Management System built into the Macintosh Operating System (Mac
OS).
Color Temperature – The color of light given off by an object, known as a blackbody, as it is
heated to a given temperature in degrees Kelvin. Low color temperatures such as 5000K are
reddish, whilst higher color temperatures such as 9300K are bluish. A color temperature of
6500K is considered to be “neutral” white.
Contrast Ratio – The ratio of the white luminance (Intensity) and black luminance (Black
Level) of the display.
Correlated Color Temperature – The closest matching color, expressed in Kelvin, of a white
point that does not lie exactly on the blackbody locus.
CMYK – The subtractive colors used in printing: Cyan, Magenta, Yellow, and Black. Note that
Black is referred to using “K” to avoid confusion with “blue”.
D Illuminants – CIE Daylight Standard Illuminants based on approximating daylight. The
subscript denotes the correlated color temperature of the illuminant. For example, D50 has a
correlated color temperature of 5000K.
Delta-E (Δ-E) – A measurement of how different two colors are to each other. In SpectraView,
Delta-E values are derived by calculating the distance between two colors in Lab color space
using the CIE 94 formula. A Delta-E value of 1 indicates a just perceptual difference between
two colors.
Delta-uv (Δ-uv) – A measure of how different two colors are, irrespective of luminance. In
SpectraView Delta-uv values are used to indicate how far a white point is from the blackbody
locus. CIE uv color space is used instead of CIE xy because it is more perceptually uniform or
linear.
Device Dependent Color – A color space that is tied to the color rendering capabilities of a
specic device. Examples are RGB color spaces that depend on the phosphor or lter colors
used on the display. Another example is CMYK color spaces that are dependent on the types
of inks and paper used.
Device Gamut – The range of colors that a device can produce.
Device Independent Color – A color space that can describe color independently of the capa-
bilities of a specic device. An example is the CIE xy color space.
DDC/CI – Display Data Channel Command Interface is a two-way communications link be-
tween the video graphics adapter and display monitor using the video signal cable.
DICOM – Digital Imaging and Communications in Medicine.
Foot Lamberts (fL) – A unit of luminance. One foot Lambert is equal to 1 Candela per meter
squared divided by 10.76/π (approximately 3.43) .