color triangle (In French triangle chromatique) see CIE chromaticity chart

color transparency, tranny, chrome, color slide (In French diapositive, transparent) analog color image original; in the age of digital photography, exists only as archive material.

color transformation (In French transformation chromatique) see gamut mapping

color temperature (In French température de couleur) measure Tx in Kelvin [K] or Mired [M] (M = 1000000/K) for the color impression of a light source compared to the luminescent color which the ideal “blackbody” (Planck radiator) gives off at a certain temperature. Three cases must be distinguished: 1) the Planckian color temperature PCT TP (température de couleur de Planck) itself, which shows this ideal body with the full absorption of incident heat radiation, whereby…

color table (In French table des couleurs) see CLUT

color system (In French système colorimétrique) system for arranging the color stimuli, it always represents only the basic principle of a color mixture and not its technical implementation.

color synthesis (In French synthèse des couleurs) combined print of the color separation files/prints

color substitution (In French technique de fausse couleur) process for increasing contrast during visual image assessment. Pure grayscales can be assigned arbitrarily selected hues with additional information (infrared: temperatures) with infrared camera images or the hardly perceptible brightness levels within one chromaticity level (e.g. leaf green hues in satellite photos to analyze forest dieback).

color strength (In French pouvoir/puissance colorante) measure for the ability of a color agent to have a coloring effect on other materials; measurable as absorptance depending on the concentration of the coloring agent in the material to be dyed.

color stimulus function (In French courbe spectrale d’un stimulus de couleur) mathematical description of the color stimulus with curves for the weakening of the luminous flux for wavelength intervals of 5 to 20 mm. Under a certain illuminant, the color stimulus function (physical “transmitter”) creates concrete standard color values with the standard spectral value functions (physiological “receiver”).

color stimulus (In French stimulus de couleur) 1) physical identification of the light radiation which, through direct stimulation of the cones (retinal receptors) causes a perception which can be felt as color. The color stimulus can come from a primary radiator (light source) as well as from a secondary radiator (remitting surface). 2) identification in terms of value of chromaticity coordinates in the color space with the help of a vector pointing from the coordinate…

color specimen book, spot-color sample book (In French nuancier, atlas des couleurs) collection of samples, printed or as PDF files, of printable chromaticity coordinates (e.g. on account of the restricted color space in newspaper printing or to extend the color space of hifi-color scales) and pigment effects.

color (space) transformation (In French transformation de l’espace chromatique) see gamut mapping

color space models and derivates (In French modèles colorimétriques et espaces colorimétriques dérivés) to extend the understanding of a color space, which is actually also a color space model, so-called derived color spaces must also be included in this discussion – specially prepared systems which can be traced back to the analysis color space CIEXYZ (device-independent) and the analysis and synthesis color space RGB (device-dependent) or the synthesis color space CMYK (device-dependent). Color spaces derived…

color space (In French espace chromatique/colorimétrique) three-dimensional representation and relation model of chromaticity coordinates. A distinction is made between device-dependent color spaces (RGB, CMYK) in accordance with the technical color channels, and device-independent color spaces (CIEXYZ, CIELAB), which represent the entire perceptible color space.

color solid (In French solide des couleurs) geometrical representation of a color model, e.g. sphere (Runge), double cone (Ostwald), rhombododecahedron (Küppers) or irregular structures (Rösch, CIELAB color space).

color separation (In French séparation/sélection des couleurs) production of color separation files/prints for multicolor printing; the color separation files/prints of the process colors CMYK must have different screen angles to prevent a moiré effect.

color separation file/print (In French sélection couleurs) imaging file or its partial printing result for each of the printing inks involved in the print process.

color rendering (In French rendu des couleurs) quality of the color appearance with which a color image is represented in the target medium, or is simulated first on a monitor or in the digital proof.

color rendering index, CRI (In French indice de rendu des couleurs) colorimetric quality of a light source for suitability for adjustment or color matching; measure for the accuracy of a color impression obtained by the illumination of a chromatic object (test colors according to DIN 6169-2:1976) compared to a D50 reference light source: Ra = 100 – 4.6 × ΔE*ab; for color-matching booths and control station desks, an index > 90 is required; the LED…