Glossary of terms

Technical terms simply explained

D50, artificial daylight 5000 K lumière artificielle 5000 K artificial daylight with a highly similar color temperature of 5003 Kelvin; standard CIE illuminant which was defined as standard in the printing industry in conjunction with the 2° standard observer field of view for the lighting conditions of printing inks, prints and proofs in color matching and at the central control console and as a white point in color transformations, ICC profile calculations and soft copy proof monitors. Resetting with fluorescent lamps (e.g. Just daylight pro- Graphic) or LEDs (patented Just LED control).

D65, artificial daylight 6500 K lumière artificielle 6500 K artificial daylight with a highly similar color temperature of 6502 Kelvin; standard CIE illuminant which is used in the
paper, textiles, plastics and automobile industries, frequently in conjunction with the 10° standard observer field of view and which cannot be transformed in this form into D50/2°.

daylight, diurnal light lumière du jour spectral radiation distributions defined by the CIE which are oriented towards different sun position and solar radiation angle phases (daylight phases) and which can be copied as “artificial daylight” with the help of technical light sources: D50 = 5003 Kelvin, D55 = 5503 K, D65 = 6504 K, D75 = 7504 K. The definition includes the respective natural UV shares of the sunlight.

DCS, Desktop Color Separation see Tables D-1 “Data file formats” on page 42

DDCP, direct digital color proof système d’épreuves couleur numériques direct direct, i.e. filmless digital color test print process, in short digital proof, usually with a claim to contract color-proof. Inkjet printing has gained acceptance as the test print method.

Default-CMM CMM standard see CMM

definition définition measure [pixel × pixel] for the number of picture elements (“pixels”) in the horizontal and vertical (line number) on monitors (must be supported by the video card of the computer or of the hardware-calibratable monitor), CCD cameras and scanners; the highest monitor resolution currently possible: QWUXGA/WQUXGA 3840 × 2400; 30-inch monitor by NEC: 2560 × 1600; HDTV: 1920 × 1080 and 1280 × 720 pixels.

Delta E, color difference/deviation delta E, dE, ΔE, différence entre deux couleurs difference between two chromaticity coordinates in a perceptually equidistant color space. It is calculated with the so-called Euclidean difference formulae, the root of the sum of the color coordinate squares – see back inside cover pages: CIELAB. To prevent confusion with color differences that were calculated using a color difference formula from a different color system, a complete Delta E specification contains as an index the reference to the color system in question, e.g. ΔE*ab for CIELAB (1976), also supplemented by the observation conditions, e.g. 2°/D50 for 2° standard observer field of view with 5000 Kelvin as illuminant. In the printing industry, the Delta E value is particularly suitable for agreeing on tolerances in standards as well as between customers and print providers with respect to the criteria for the accuracy of color reproduction in accordance with ISO 12647 or PSO or even closer tolerances in individual cases. Practical statement of the Delta E value: 0.0 to 0.2 “unnoticeable” (non perceptible), up to 0.5 “very small” (très faible), up to 1.0 “noticeable” (perceptible), up to 1.5 “small” (faible), up to 2.0 “just right noticeable” (tout juste nettement discernable), up to 3.0 “distinctive” (nette), up to 4.0 “marginally disturbing”
(peu gênante), up to 6.0 “medium, very distinctive” (moyenne, très nette), over 6.0 “large, disturbing” (importante, forte, gênante).

densitometer densitomètre measuring device with which the optical density or color density (light obscuration) is determined as a indirect measure for the layer thickness of the printing ink. The thickness measurement requires a polarization filter which compensates for the differences between wet and dry ink layers. Compared to obsolete devices with the optical filters R, G, B and Vis (for measuring of black ink), densitometers today work with a spectral scanning head and calculate the density values virtually. Measuring filter characteristics and device calibration (with reference to paper white or absolute white) differ in geographical markets: Europe: “Status E” (ISO/ANSI E, DIN 16536, broadband with respect to paper white, higher yellow values than Status T), America: “Status T” (ISO/ANSI T, broadband with respect to absolute white), “Status I” (ISO/ANSI I, DIN 16536 NB, narrow band with respect to paper white); furthermore “Status M” (broadband measurement of transmitted light), “Status A” (only photographic industry, broadband reflected and transmitted light measurement).

desaturation désaturation removal of chromaticness in intuitive image processing tools and in monitors.

destination profile profil cible see Tables I-2 “ICC profiles classification” on page 56

detail rendering/rendition rendu des détails quality of information transmission with respect to detail in all tone value ranges, including noise and resolution limits; detail and color rendering are influenced jointly through changes in the printing characteristic.

deuteranomaly deutéranomalie color vision deficiency; red receptor weakness,  magenta-cyan metamerism.

deuteranopia deutéranopie color vision deficiency; red receptor failure, magenta-cyan confusion.

Deutsches Farbenzentrum, German Color Center central institute for color in science and design with its main office in Berlin; representative for all professions that deal with color.

device-independent reproduction/processing traitement indépendant du matériel ICC profile-based workflow scenario in which the image and graphics data are processed, saved and passed on in a process-neutral color space format (large RGB working color space, less frequently TIFF-LAB), in order to be able to represent the output in any possible medium (print in various printing processes, electronic media, presentation) with maximum color rendering quality; at the same time, device-independent reproduction is a precondition for the simultaneous output in several of these media (“crossmedia”) and requires the use of a content management system which keeps the images and all other content available in a medium-neutral form.

device profile profil de périphérique ICC profile that is available in a device color space (input and reproduction: RGB; output: CMYK) and characterizes a concrete device or class of device.

(device) profile creation(color space) targeting création de profil the calculation of an ICC profile from metrologically recorded characterization data.

(device) profile linking/connecting liaison de profils regulation or procedure within the framework of gamut mapping for linking two device profiles with each other through a PCS or directly (DeviceLink). In this process, a rendering intent that prescribes the manner of this gamut mapping is also always used.

device/native color space espace colorimétrique natif color space whose color channels result from the technical circumstances of the color analysis (RGB photography/scan) or color synthesis (CMYK printing).

DeviceN color space type supported from PostScript 3 and PDF 1.3 upwards, which allows arbitrary combinations of color channels in composite files (PostScript, PDF) and in In-RIP separations, thus preventing the subsequent output of the color separation files being reduced to the 4 process color extracts CMYK. Frequent cases in practice: 5 or 6 Pantone hexachrome colors, CMYK plus 2 special colors, black plus 1 spot color – that is, typical color impositions on modern sheet-fed offset presses. What is practical in the use of DeviceN is ICC profile creation software for more than 4 color channels or, if only one CMYK proof system is available, profile editing software which optimizes the rendering of special colors in CMYK profiles, e.g. basICColor MatchPatch.

dfwgGerman Society of Color Science and Application Mirror committee for the CIE divisions 1 (Vision and Color) and 8 (Image Technology), whose members from industry and research work on the dissemination and improvement of color measurement, colorimetric research results and new application procedures.

DHDDigital High-Definition filmless high-resolution cinema recording and editing process; suitable ICC programs carry out color corrections for entire cinema films and allow decentralized, color-identical copying for worldwide distribution; the first DHD film was “Rainbow” (USA, 1995).

DIC Scale Japan Color standard colorimétrique DIC counterpart to the Euroscale, developed by the Dainippon Ink Corporation (DIC) for the Asian market; was taken into account in the colorimetric definition of the worldwide ISO scale 2846-1:2006.

dichromatopsia dichromasie color vision deficiencies in which only 2 of the 3 types of retinal cone work normally.

diffraction and refraction diffraction et réfraction with respect to the spectral colors, the following laws apply: 1. When light is diffracted at edges, cracks and optical lattices, red is diffracted more than blue (e.g. light dispersion in color meters, color holograms). 2. When light is refracted as it passes into transparent solids/liquids/gases of other densities, blue is refracted more than red (dispersion spectrum, e.g. prism, rainbow).

diffuse diffus scattered; property of light rays that are reflected/remitted from a more or less matt or rough surface; opposite: directional. Spectrophotometers that are used on high-gloss or curved surfaces (plastic foils, metals, leather, stained glass etc.) have a spherical scanning head (integrating sphere) in which the light to be measured is first scattered and then measured at an angle of 0° or 8° above the surface (geometries di:0°, di:8°).

digital printing impression numérique group of printing processes which work without a fixed print form; used instead of conventional printing inks, electrophotographic toners (powder-like, only “liquid” for the HP indigo press), inkjet inks (with dyes or pigments, on a solvent or water basis or UV-curing) or transfer materials. Digital printing supplements high-circulation and static printing processes in their uneconomic areas. digital/electronic photography photographie numérique photographic process which uses a digital image memory instead of analog image recording material (film); digital camera backs (dos numérique) have been developed for high-quality conventional cameras.

DINGerman Institute for Standardizationorganisme allemand de normalisation German standard setting body; for the fields of light and color, several standards committees (FNF, FNL, NPF) are responsible; the development of the standards proposals is the responsibility of the technical associations and industry organizations, e.g. BAM , bvdm, ECI.

direct digital proof épreuve numérique directe test printout for various purposes: definition or check of contract color reproducibility (within the framework of ICC color management – see DDCP), print reproducibility (screen proof with authentic print screening), color design (design proof) or layout (e.g. arrangement of packages/labels on the print sheet, representation of register lines etc.);

directionalspecularly spéculaire possible property of incident and emergent light rays; opposite: diffuse.

dispersion dispersion statistical variable. display colorimeter colorimètre pour moniteur see colori -meter

display profile profil moniteur/d’écran ICC profile calculated from characterization data recorded with a display colorimeter. Such software profiles are considerably less accurate than a hardware calibration with 10, 12 or 14 bits.

Display 1) écran Monitor, today using LCD TFT technology; characterization through ICC reproduction profiles. 2)support de PLV advertising material with more or less complicated design, which at the same time can serve as transportation packaging and/or goods shelf; this highly specialized product of the packaging printing and folding box industries often represents part of an advertising campaign (at the “Point of Sale”) and on account of the consistently uniform design sets very high standards concerning the color rendering of the individual products involved (on displays, posters, prospectuses, labels and in mail order catalogs, TV commercials etc.); displays are available for example as stand-up cards, banners, crowners, ceiling-mounted objects (as posters, mobiles or with electric motors), dispensers (for goods and prospectuses), display walls (sometimes arranged with illuminating bodies, with which adjustment has already to be carried out at the reproduction stage), pallet trays, presentation packaging, prismatic displays, shelf inserts, drawers, bases, wobblers/ whippers; the surface, which is frequently printed with more than the four process colors, is often also varnished or laminated

dithering juxtaposition (de pixels) 1) Scattered screening through error diffusion 2) unpractical pixel scatter with which the missing chromatic color shares are reproduced from available color shares.

dot gain, tone value increase (TVI) augmentation de la valeur tonale (AVT), élargissement du point de trame in tone value transmission processes, generally prevalent change in tone values between dataset and print. When chromatic tone values are being transmitted, chromaticity shifts occur; with more exact knowledge of the transmission process, however, these can be taken into account to achieve the desired color rendering. Cause: dot widening in offset printing, depending on the printing ink consistency (sheet-fed offset, heatset, coldset, UV, waterless), substrate, screen ruling and modulation.

dot/screen percentage, halftone/screen value pourcentage de trame, valeur de trame relation between screen density and solid density (Murray-Davies formula), possibly taking account of the light trap (Yule-Nielsen correction). Print and tonal value increase characteristic curves, which as tone reproduction curves (TRC) are important components of color management, refer to dot percentages.

downsampling sous-échantillonnage reduction with losses of the number of pixels in an image file when the format is reduced in size. The reduction of color depth (e.g. from 16 to 8 bits per color channel) is also often referred to as downsampling.

dpi, dots per inch ppp, points par pouce Unit of measure for the resolution of output devices

dropout colors couleurs aveugles colors that are not detected by a grayscale scanner or black-and-white copier; application: forms for automatic document scanning.

dryback virage difference in color density values resulting from the densitometric measurement of the damp (higher) and the dried (lower) printing ink.

drying behavior vitesse de séchage adaptation by the manufacturer of the printability and drying properties of a mainly oxidatively drying printing ink with the help of additional substances to the technical printing conditions and substrates, e.g. duct-fresh (encre fraîche), roller-fresh (encre demi-fraîche) and penetrating (encre siccative). Drying behavior embodies the best possible compromise between problem-free printability (no drying in the inking unit) and good drying.

drying by oxidation séchage par oxydation chemical drying principle of offset printing inks through oxygen bridge bonding between the binding agent molecules.

DTP, desktop publishing PAO, publication assistée par ordinateur “Publishing from the desktop”; form of digital document creation which at the beginning of the 90s replaced the earlier form of production with dedicated, manufacturer-specific closed hardware-software systems. This created the necessity and at the same time the opportunity to make production color-consistent with data exchange between open systems (color management), which led to the establishment of ICC in 1993.

duplex, duo-tone double-ton, duplex Image with a high-contrast single-color black structure, which is underlaid with a flat chromatic color. Depending on the desired effect, the chromatic color can intervene in part-areas of the gradation or atall tone value levels.

dye, dyestuff colorant several classes of mostly synthetic color agents, which unlike pigments, which color the objects fully, only color up the objects; about 7000 dyes are classified in the Color Index.

dynamic color measurement mesure colorimétrique dynamique spectral or camera-based measurement of colorimetric variables on a moving object (print sheet, web); opposite: static measurement (on a stationary sheet/web section).

dynamic/tonal range étendue des tons difference in brightness between the lightest and the darkest tone values in a reference or of an input device that can detect this difference.