Glossary

Abnormal Color Vision
Defective color vision blindness, which may take the form of protanopia (red and bluish green confusion); protanomalous deficient in red response for certain color mixtures); deuteranopia (red and green confusion); deuteranomaly (deficient in green response for certain color mixtures; tritanopia (blue and yellow confusion); and monochromatism (no discrimination of hue and saturation).

Absorption
The taking up of light energy by matter and its transformation into heat. Selective absorption of the range of wavelengths compromising white light produces colored light.

Achromatic
The term used to refer to white, grays, and black which have no hue.

Actinic
Describes the ability of light to produce changes in materials exposed to it, such as photographic emulsions.

Actinic Density
The density of a color, relative to a density positive gray scale, when recorded on a given photographic emulsion.

Additive Color Process
A means of producing a color reproduction or image by combinations of blue, green, and red colored lights, such as in color television systems.

Additive Primaries
Blue, green, and red lights of high saturation, which when mixed together in varying combinations and intensities can produce any other color.

Additivity Failure
A common condition of printing ink on paper where the total density of the overprinted ink films is not equal to the sum of the individual ink densities.

Adjacent Color
The visual influence of a color area on an adjacent color. This effect is especially strong when the adjacent color area is relatively large and has high saturation.

Afterimage
Sensation that occurs after the stimulus causing it has ceased. Because of cone fatigue, the colors of the afterimage may be complementary to those registered initially.

Airbrushing
Retouching of prints or artwork by dyes or pigments sprayed on with high-pressure air from a small hand-held sprayer.

Alpha Channel
An 8-bit channel reserved by some image-processing applications for masking or additional color information.

Analog
Electrical signals of continuously variable frequency or intensity. These signals can be generated by photocells or photomultipliers and are related to the density of an original. Many color scanners use analog circuits.

Apochromat
A lens used for color separation work. This lens will bring the red-, green-, and blue-light bands of the spectrum to the same point of focus.

Artifact
A visible indication (defect) in an image, caused by limitations in the reproduction process.

Balanced Process Inks
A set of process inks of which the ratios of the blue and green actinic densities of the cyan and magenta are equal, enabling the use of only one color correction mask for the yellow.

Banding
A visible stair-stepping of shades in a gradient.

Black
The absence of color; an ink that absorbs all wavelengths of light.

Black-light
A source rich in ultraviolet and low-frequency blue radiation source.

Black printer
The plate used with the cyan, magenta, and yellow plates for four-color process printing. Its purpose is to increase the overall contrast of the reproduction and, specifically, improve shadow contrast. Sometimes called the key plate. The letter K is often used to designate this color. See Full-Scale Black and Skeleton Black.

Blanket
A fabric coated with natural or synthetic rubber that is wrapped around the blanket cylinder of an offset press. It transfers the inked image from the plate to the paper.

Brightness

The amount of light reflected from a surface.
A paper property, defined as the percentage reflection of 457 nanometers (nm) radiation.
The intensity of a light source. 4. When used to describe color, this term means highly saturated.

Bronzing
In process-color printing, the effect that appears when the toner in the last color often black) migrates to the surface of the printed ink film, causing a change in the spectral aspect of surface light reflection.

Bump Exposure
A brief no-screen exposure that supplements the main exposure when making a halftone. The effect is to compress the screen's density range without flattening tonal detail. The technique produces a full range of halftone dots from short-density-range copy and can also be used to expand highlight or shadow tonal separation, depending on whether negatives or positives are being made.

C print
A term used by some to describe any reflective color print. The term was used to designate a particular Eastman Kodak integral tripack color print material.

Calibration bars
On a negative, proof or printing piece, a strip of tones used to check printing quality.

Carbon black
The pigment commonly used in black inks. Toners are usually combined with this pigment in the ink formulation to make the black ink more neutral.

CC filter
Color compensating filter, a high transmittance filter used to correct the color balance of transparencies. CC filters are available in six colors and several strengths.

Characteristic Curve
Graphical representation of the relationship between the exposures given to a sensitized material and the corresponding image densities produced under specified development conditions.

Chroma
The degree of saturation of a surface color in the Munsell System.

Chromaticity Diagram
A graphical representation of two of the three dimensions of color. Intended for plotting light sources rather than surface colors. Often called the CIE diagram.

Chrome
A term used to describe a color transparency. It is a contraction of brand names such as Kodachrome, Fujichrome, Ektachrome, or Agfachrome.

Chrome Yellow
An inorganic pigment that is primarily lead chromate, used for making opaque yellow inks.

CIE
Commission Internationale de l'Eclairage, a standards-setting organization for color measurement.

CIE Diagram
See Chromaticity Diagram.

Cleanliness
Synonym for high saturation.

CLUT
Color look-up table.
See Look-up Table.

CMYK
(cyan, magenta, yellow, black) The subtractive primaries, or process colors, used in color printing.

Color Balance
The combination of yellow, magenta, and cyan needed to produce a neutral gray. Determined through a gray balance analysis.

Color Bars
See Color Control Strip.

Color Blindness
See Abnormal Color Vision.

Color Cast
The modification of a hue by the addition of a trace of another hue, such as yellowish green, pinkish blue, etc.

Color Chart
A printed chart containing overlapping halftone tint areas in combinations of the process colors. The chart is used as an aid to color communication and the production of color separation films. The charts should be produced by individual printers using their own production conditions. See Foss Color Order System.

Color Circle
A GATF color diagram used for plotting points as determined by the Preucil Ink Evaluation System. The dimensions are hue error (circumferentially) and grayness (radially). See Preucil Ink Evaluation System, Color Triangle, Hue Error, Grayness.

Color Control Strip
Small patches of color solids, overprints, tints, and resolution targets for the purpose of monitoring printing press performance. Sometimes called color bars.

Color Conversion
A color transparency made from a color reflection original. A conversion is made for the purpose of allowing a rigid reflection copy to be color-separated using a drum-type scanner, or for any of the other reasons listed under color duplicating.

Color Correction

A photographic, electronic. or manual process used to compensate for the deficiencies of the process inks and the color separation process.
Any color alteration requested by a customer.

Color Duplicating
The process of making a duplicate transparency from an original transparency for purposes of retouching, color cast adjustment, density range normalization, image assembly, or reproduction scale adjustment. Color duplicates are sometimes called dupes.

Color Gamut
The range of colors that can be formed by all possible combinations of the colorants of a color reproduction system.

Color Hexagon
A trilinear plotting system for printed ink films. Adapted for the printing industry by GATF, the method was originally developed by Eastman Kodak. A color is located by moving in three directions (at 120 degree angles) on the diagram by amounts corresponding to the densities of the printed ink film. The diagram is generally used as a color control chart, particularly for detecting changes in the hue of two-color overprints.

Color Proof
A printed or simulated printed image of the color separation films. The colorants used are selected so that the proof will produce a close visual simulation of the final reproduction.

Color Quality Index
See Color Rendering Index.

Color References
A given set of inks printed at specified densities or strengths on a given substrate, used for color control.

Color Rendering Index
A measure of the degree to which a light source, especially a fluorescent light, under specified conditions, influences how the perceived colors of objects illuminated by the source conform to those of the same objects illuminated by a standard source, which is usually some aspect of daylight. Also called color quality index.

Color Reproduction Guide
A printed image consisting of solid primary, secondary, three and four-color, and tint areas. It is primarily used as a guide for color correction of the defects of the printing ink pigments and the color separation system. The guide should be produced under normal plant printing conditions.

Color Scanner
See Scanner.

Color Separation
The process of making film intermediates from the color original to record the red-, green-, and blue-light reflectances. These films are used to prepare the cyan, magenta, and yellow printing plates. A black separation is also made.

Color Sequence
The color order of printing the yellow, magenta, cyan, and black inks on a printing press. Sometimes called rotation or color rotation.

Color Temperature
The temperature, in degrees Kelvin, to which a black body would have to be heated to produce a certain color radiation. 5,000 K is the graphic arts viewing standard. The degree symbol is not used in the Kelvin scale. The higher the color temperature, the bluer the light.

Color Transparency
A positive color photographic image on a clear film base. It must be viewed by transmitted light. Sizes range from 35-mm color slides up to 8x10-in. (203x254-mm) sheet film transparencies.

Color Triangle
A GATF color diagram based on the Maxwell Triangle for plotting points as determined by the Preucil Ink Evaluation System. The dimensions are hue error (circumferentially) and grayness (radially). Color masking, color gamut, and ink trapping may be determined from the diagram by using simple geometric techniques. See Preucil Ink Evaluation System, Color Circle.

Colorimeter
An optical measuring instrument designed to respond to color in a manner similar to the human eye.

Comp
Comprehensive artwork used to present the general color and layout of a page.
See Color Proof.

Continuous Tone
Variation of density within a photographic or printed image, corresponding to the graduated range of lightness or darkness in the original copy or scene. Sometimes referred to as contone.

Contone
See Continuous Tone.

Contrast
Differences between light and dark tones, including the visual relationship of the tonal values within the picture in highlight, middletone, and/or shadow tones.

Copy
Any material furnished for reproduction. For color printing it may be a color photograph (print or transparency), artist's drawing, or merchandise sample. Sometimes called original copy.

Cromalin
A color proofing system that uses powdered pigments instead of ink.

Cyan
The subtractive transparent primary color that should reflect blue and green and absorb red light. One of the four process-color inks. Sometimes called process blue.

DCS
See Desktop Color Separation

Densitometer
An electronic instrument used to measure optical density. Reflection and transmission versions are available.

Educational Materials for Digital Printing