Glossary of terms
Technical terms simply explained
tack tack, tirant rheological parameter; resistance which a layer of printing ink shows to its separation; can also be interpreted as adhesive power per surface (adhesive tension); unit of measure Pascal or manufacturer-independent scale values (Inko: IGT-Tacktester, Tacko: Testprint Tack-o-Scope); the tack of printing inks is optimized to rule out picking; see also ink stringing
tackiness , stickiness poisseux Totality of subjective evaluation criteria for high tackiness, highly pasty consistency, high viscosity.
tag balise defined data field (“tag”) in the TIFF-like ICC Profile Format:, which contains preformulated entries in accordance with the ICC profile format specification, e.g. the AtoB0Tag, which prescribes a color transformation between device and PCS using a look-up table.
tagging , attaching, embedding incorporé in an ICC-conforming application, the linking of a device profile or working color space (always together with a color reproduction intention) with a graphic or document file; the profiles remain not only readable and interpretable, but also extractable using suitable tools (basICColor profile genie).
TCB , Techkon Color Book fixed value tables defined in CIELAB, a spectral luminance factor or spectral density for color libraries in Techkon spectrodensitometers (HKS color libraries preinstalled) with optimized color values incl. meta information (measuring mode, paper white coating etc.); can be generated itself in conjunction with the Techkon Connect software from measured color and density values. TCB corresponds to ISO 28178, which the color table format ANSI CGATS.17 must be converted to at the end of 2011.
temperature window temperature-dependent viscosity range in which an offset printing ink can be printed optimally; modern printing presses are equipped with an inking unit temperature control unit for this.
tertiary colors, pastel tones couleurs tertiaires, tons pastel color shades that are mixed from at least 3 primary colors or from primary and secondary colors, e.g. brown, skin tones etc. test chart, target, patch chart, test form: in color management the templates including reference file for the characterization of input and output devices, e.g. ECI2002, IT8.
testers appareils de contrôle indispensable systems for testing the properties of printing inks as well as their interactions with substrates; most important suppliers: Fogra, Elcometer Instruments, IGT, IGT emus, PITSID, prüfbau, Tappi.
TFT , Thin Film Transistor transistor couches minces see active matrix LCD
thinner, dilutant diluant colorless additive which lowers the viscosity in order to improve runability (offset: oils ensure improved tack) or to allow it (flexo printing); thinners influence color rendering in print.
thixotropy rheological property of some inks which when delivered are highly viscous (e.g. UV inks or highly pigmented wide gamut inks) in that their viscosity can be lowered through an ink agitator in the ink duct or ink splitting in the inking unit, thus allowing a favorable processing consistency to be achieved; at the end of agitation the ink returns to its high initial viscosity.
three-color gray gris trichrome gray tone obtained when the three chromatic printing inks CMY are printed together. Since three-color gray reacts particularly sensitively to changes in the inking metering of a printing press, the gray balance is especially suitable for quality control in production printing and basically also in setting up. System Brunner invented the control strategy with gray balance priority, and optimized it with Instrument Flight (the full version is also available with KBA QualiTronic Color Control or with QTI CCS).
three-dimensional quality of color vision trivariance visuelle, loi de Grassmann property of color perception of being able to be described with 3 parameters each: Basic valences PDT, opponent color theory axes red-green/yellow-blue/blackwhite, primary valences RGB, standard valences XYZ, physical color mixing CMY, intuitive attributes hue, chromaticness, brightness.
TIC couverture d’encre totale see total ink coverage
TIFF , tagged image file format ISO file format for representing images as pixel graphics files; color channels: monochrome, RGB, CMYK, L*a*b*, colored grayscale images in DeviceN, N=2; 8-bit alpha channels; five loss-free compression methods. Derivatives: TIFF/IT describes an image file format tailored to the special features of medium-independent image processing and allows ICC profile embedding. TIFF-G4 (1-bit TIFF) as a separation output format for printing plate illustration is just as suitable for the real time reconstruction of a soft copy proof at the printing press central control console, especially in newspaper printing, in that the printed sheet appearance can be simulated on the monitor to a contract-proofed level through descreening and decalibration. TIFF/EP is the image file format for digital photography as an alternative to RAW.
time elapse meter compteur d’heures de fonctionnement Numerical display on color matching booths and standard light luminaires; documents the aging of the light source for the purpose of the point in time of its necessary replacement.
tolerance tolérance permissible deviation with respect to a specified objective; application for example in contract proof criteria.
tone (value) tonalité, valeur tonale relative brightness degree, (i.e. with respect to a minimum (e.g. paper white) and a maximum (solid tone). The tone value can be reproduced without structure as a continuous tone (measurable as optical density) and with structure as a pixel tone or half tone (measurable as integral optical density) and also as color value (measurable as color density and/or chromaticity coordinates).
tone reproduction curve , TRC courbe de reproduction tonale 1) curve of a color separation file/print; relation of the screen values of a color separation print compared with the original data, whereby the average rise of this characteristic print curve is defined as the gradation value (gamma). 2) in digital image processing programs, the TRC, besides global color and tonal correction, is processed directly to create contrast and coloring effects. 3) in ICC profiles the characteristic curve of the individual color channels (redTRC, greenTRC, blueTRC), effective in the link between PCS and the device
toner toner powder-like printing ink (particle size 5 to 30 μm) in electrophotographic printing systems; contains pigments, synthetic resins (thermal fixers), electrostatically chargeable or magnetizable metal oxides and auxiliary substances to influence flow properties; dispersion of smaller particles (1 μm) possible as liquid toner for offset quality (Toyo Electro Ink for HP indigo press).
total ink coverage , TIC couverture d’encre totale ink layer thickness resulting from the combined printing of all printing inks involved in the process; from the point of view of preprinting, defined as “maximum tone value sum”. In four-color printing, total ink coverage can theoretically amount to up to 4 ×100% = 400%, which would lead to unwanted delays in drying and associated printing problems, which can be avoided by using a modified ink composition process (UCR, GCR, GCC). With the help of software for saving printing ink, preset ink composition settings can be used, applying ICC ink transformations between problematic and optimized output color spaces (DeviceLink) or already preset DeviceLink profiles (basICColor DeviL and DLpack). Total ink coverage must be reduced particularly sharply in newspaper printing, because the paper used there is most absorbent.
total ink quantity quantité totale d’encre control factor in the process of printing ink transfer onto the substrate; can be calculated by determining the mass in g/m² per print sheet, in order to be able to calculate ink consumption.
translucency translucidité shine through of light, e.g. translucent paper.
transmission transmission passage of light through a transparent medium; counterpart to remission on opaque surfaces.
transmitted colors couleurs par transparence surface colors of clearly transparent objects (e.g. glass, color filter).
transparency transparence property of being able to see through foils, filters and other media which allow a more or less clear view through them. Application: color filter, polarizing filter.
transparent inks encres transparentes printing inks for multicolor screen printing. The glazing behavior, i.e. the medium covering ability, is a precondition for the functioning of the autotypical color blending in which not only side by side printing but also overprinting of the halftone dots (and solid areas), including paper white, flows into the result.Example: Overprinting the solid areas of yellow on magenta creates red, because yellow lets through radiation elements of magenta.
trichromatic vision trichromasie normal vision, correct color daytime vision with the 3 fundamental stimuli PDT.
tristimulus color space, CIE color[imetric] system, CIE XYZ system of color space vectors (color stimuli) that were derived from the color perception primary stimuli RGB in order to bring together physiological color vision and the physical color stimulus causes. X is derived from R (retinal receptors generating red), Y from G (green) and Z from B (blue). The tristimulus color space represents the totality of all perceptible colors, but is purely mathematically constructed and thus not perceptually equidistant – see cover flap.
tristimulus measurement , trichromatic colorimetry mesure trichromatique see colorimeter
tritanomaly tritanomalie color vision deficiency; blue receptor weakness, blue-yellow metamerism.
truecolor file fichier truecolor image file with 8 bit per pixel per color channel R, G, B; theoretically, 23×8 = 16777216 hues can be represented.
TVI AVT see dot gain