paper papier the most important substrate for the graphic industry. Usually, as high a whiteness degree as possible is aimed for (bleaching, optical brightening). Other properties relevant for color rendering: roughness and absorptive capacity (ink trapping and drying behavior), proportion of wood pulp (yellowing propensity), surface finishing (glazing, matt and gloss coating, aluminum vapor-plating etc.), opacity (paper thickness, fillers). Modern paper manufacturers like Arjowiggins place most emphasis on color rendering and whiteness, on an equal footing with ecological requirements (high pro -portion of recycling fibers, FSC certification); two-sidedness (difference between felt and wire side) is negligible today.
paper white blanc du papier, blancheur du papier reference value for color density measurement (except in the USA) and hue to be simulated in digital and soft copy proof. Depending on the simulation requirements in digital proof printing, the suitable rendering intent is selected for the gamut mapping of the printing process color space to the proof printer color space – see profile linking.
patch plage de mesure element in ink control strips, grayscale wedges, test print formes etc.
PDF, Portable Document Format format de document multi – plateforme object- oriented format .pdf (ISO 32000) developed by Adobe and used within the framework of the document exchange program Acrobat, with which cross-platform documents can be represented in their original typography and appearance. PDF has largely displaced PostScript in the modern output workflow and is adapted there to the general physical conditions of the target printer in that the PDF pages are checked for errors (“preflight check”), imposed in the print format and finally separated in color separation files/prints.
See also composite file, PDF/X
PDF Print Engine , APPE free module by Adobe for software developers who want to integrate an elegant output solution in their applications. The APPE expects PDF documents and then processes these into output documents for multicolor printing without taking the PostScript detour, using ICC profiles, for example for soft copy proof images on the monitor, half-tone illustration files for CtP printing plate image setters or output files for digital proof and digital printing.
PDF/X, PDF for Blind Exchange PDF pour un échange aveugle ISO standards and GWG conventions explaining and defining special requirements and test criteria for the unseen exchange, that is, color-consistent and without correction, of PDF documents for multicolor printing (White Paper, ISO 15929)
pearl factor accrochage d’après Ritz see ink trapping (according to Ritz)
pearlescent /lustre/nacreous pigments pigments perlescents/à effet de perle the most popular group of interference pigments, which offer not only a special shimmer but also in some cases color flop effects; prepared from mica schist by BASF/Ciba, Eckart (Pearlstar, Phoenix), Kremer (50000), Merck (Iriodin, Pearlets); formulae mainly for gravure, flexo and screen printing, but with smaller particles also for sheet-fed offset; pearlescent pigments develop their sheen best on smooth surfaces, especially on matt-coated papers.
(perceived) color attributes attributs de couleur perçue intuitive color attributes: brightness, hue, chromaticness.
perception perception physiological process (e.g. vision) causing a sensation in the brain (e.g. color vision, color sensation, color impression); see also rendering intent
perfecting inks encres pour impression recto-verso fast-drying offset printing inks on the recto side of a print sheet, which cannot smear on the impression cylinder after the sheet has been turned in multi-color presses.
phosphorescence phosphorescence see luminescence
photoflux flux lumineux see luminous flux
photoinitiator essential component of UV inks and varnishes; depending on the type, the photoinitiator decomposes into highly reactive radicals or cations, which trigger a polymerization chain reaction in binding agents and thus ensure film formation and full hardening. Offset inks with photoinitiators that are geared to narrow-band UV sources (Excimer, LED arrays) are having trouble gaining acceptance. Photoinitiator fission products can migrate in food packaging.
photometer , illumination meter luxmètre measuring device for determining luminance (cd/m²) or luminous intensity (cd). In particular in the calibration of soft copy proof- to-press jobs, the ambient brightness, that is, the dimmed light of the standard light luminaire on the illuminated desk in front of the integrated wide-gamut monitor, should be included in monitor calibration and validation. So far, this integrated concept is offered only by basICColor (Discus colorimeter), Just Normlicht (USB-controlled dimmable standard light luminaire) and K-Flow and wobe Team (soft copy proof-to-press solutions).
photometry light measuring technology.
photon , quantum of light photon light particle that also shows wave properties (wave-particle dualism) and is emitted when an excited electron returns to its normal state (“quantum leap”). The type of atom (chemical element/compound) is responsible for the impulse energy which the photon receives in the course of the quantum leap. The wavelength of the light is the quotient of Planck’s constant h and impulse.
PhotoYCC image data format .pcd developed by Kodak specially for the photo CD in the YCC color space model with brightness Y, Cb blue-standardized red-green chrominance and Cr red-standardized blue-green chrominance.
physical color mixture, absorptive interference synthèse soustractive, interférence d’absorption incorrectly called “subtractive color mixture” (as opposite of additive color mixture); mutual absorptive influence of object colors (e.g. merged opaque paints, superimposed printing ink layers, transparent color filters arranged in series). In absorptive interference, nothing is mathematically subtracted; instead, all those parts of the irradiated light that are not re-emitted and thus are not involved in the formation of a color stimulus (Lambert-Beer’s law) are absorbed (i.e. multiplied with absorption degrees < 0). The maximum possible result “black” is to be understood as total absorption, that is, the complete attenuation of light. The absorptive primary colors are the complementary colors of the additive color mixture, that is, cyan, magenta, yellow (CMY). Applications: “autotypical color mixing” in multi-color halftone printing, color films, color formulating systems.
pigment concentrates concentré de pigment Basic range of pigment preparations in various chromatic and achromatic color shades, from which any quantity of any process or special ink can be blended in flexo and gravure packaging printing works with the help of ink blending software and computer-aided metering technology, adding wastage and solvents.
pigment preparation, master batch concentré pigmentaire preliminary product in the production of printing inks; form delivered to printing ink manufacturers, but also to flexo and gravure printing works with ink mixing and metering facilities.
pigmentation pigmentation categories for printing inks:“normal” (standard scales) and “high” (intensive scales).
pigments pigments natural or synthetic, organic or inorganic color agents which are incorporated as powders or pastes in binding agents for paints and printing inks as well as inkjet inks, in which they are practically insoluble. Unlike coloring dyes, they have a coloring-through effect, i.e. they provide not only chromaticity coordinates but also a degree of opacity. Approx. 600 pigments are classified in the Color Index. Process color pigments: beta-phthalocyanine blue BN (C), lithol rubine BK (M), benzidine (Y), soots (K). See also effect pigment inks
pixel , picture element pixel 1) smallest addressable component of an image file with a certain data depth (see bit depth). The pixel size corresponds to the size of the sensors or recording resolution in the input devices and can lead to aliasing when describing contours. 2) image element of an active matrix display, in which however the RGB subpixels are the smallest addressable components.
pixel graphics file image matricielle/en mode point simulation of a continuous halftone image composed of elements (pixels) arranged as in a halftone screen; disadvantage: when the scale is changed, interpolation pixels are created between the original pixels, and these have an adverse effect on sharpness and color rendering.
Planckian radiator, black body radiateur de Planck, corps noir ideal hollow body which completely absorbs light reaching it through a small opening, and which thus heats up and glows. As the temperature rises, the glow passes through various luminescent colors(see color temperature); this curve is marked in the CIE chromaticity chart as Planckian locus.
point of smearing limite de graissage desirable offset printing setting of the ink-dampening solution balance, in which as little water as possible is used to keep the non-printing gaps just free of ink, that is, at the limit of scumming; which conversely means over-inking (smearing); opposite: water marks
polarizing filter , polarizer, polaroid filtre polarisant filter which allows radiant or reflected light to pass only in one oscillation direction of the wavelengths; application: prescribed (except for USA) in densitometric measurement to be able to eliminate differences in gloss between wet ink immediately after printing and dried printing ink; optional for color measurements on metallic color prints.
poster inks encres pour impression d’affiches sheet-fed offset inks with high light fastness and fast oxidative drying through.
PPF , print production format see CIP4
ppi, pixels per inch pixels par pouce see definition
press proof épreuve machine an individual color separation and associated combined print of the color separation produced on a press proof machine (in particular sheet-fedgravure); is gaining importance again for complicated color printed products to rule out metamerism phenomena in the original pigments.
primary/basic colors couleurs primaires arbitrarily chosen color shades, from the mixture of which other random color shades are to be created; primary colors in additive color mixing: R, G, B; primary colors in physical color mixing: C, M, Y.
(primary) color channel canal couleur component for representing color information in scanners, digital cameras, monitors (RGB) and graphic data formats (RGB, CMYK).
primary source source primaire see light source
primary stimuli, primaries stimulus de couleur de référence mathematical model for the value-based identification of a color stimulus in additive color mixing; derived from the basic stimuli of the 3 cone types, the real color stimuli R, G, B characterize the color signal absorption in the 3 color channels of the eye; CIE(1931) definitions of the primary stimulus wavelengths λ and the related relative spectral radiation distribution S(λ) for the equi-energy spectrum (illuminant E) and the 2° standard observer: λR = R = 700.0 nm and S(700) = 72.096; λG = G = 546.1 nm and S(546.1) = 1.379; λB = B = 435.8 nmand S(435.8) = 1. Technical definitions of primary stimuli are for example the color filters in a color scanner or the subpixel colors of LCD monitors.
print quality qualité d’impression Grade of printed image reproduction, depending above all from the interaction between printing ink and substrate; quality control takes place in all phases of the print value-added chain, whereby it is also possible to observe the quality status via the Internet as well as over long periods of time (“quality monitoring”, e.g. iQIP by impakt medien).
print run paper/stock papier du tirage the print stock identical to the print run, whose color coordinates (“paper white”) are to be simulated in the color workflow.
printability imprimabilité suitability of a substrate for a printing process all mechanical, optical and thermal properties of a substrate that are relevant for the interactions with the ink, in particular smoothness, absorptive capacity, oil absorption, pick strength, surface tension and pH-value.
printing ink encre d’impression pasty-viscous to watery mixture of color agents, film formation agents and possibly also solvents, auxiliary materials and additives. The purpose of printing ink is to achieve light-dark and or colored contrasts on the substrate. Depending on the printing process (printing ink transfer, in offset printing also the wet and waterless wetting principles) and absorbency of the substrate surface (ink absorption capacity) the stable adhesion of the color agents is induced using different principles of ink drying. Other technical requirements concern spectral properties, gloss, covering capacity, light fastness, chemical and mechanical resistance, environment-friendliness (freedom from hazardous substances, migration behavior, deinking/recyclingcapacity, possibly binders from vegetable oils), also special pigment effects (reflection, fluorescence). Classification by application is also possible: book printing, printing on lightweight paper, illustration/art printing, securities printing, newspaper etc.
printing ink sequence ordre d’impression des couleurs, séquence des couleurs in multicolor printing, the sequence of the printing of the process colors or other chromatic colors on the substrate; the standard offset printing process prescribes KCMY for sheet-fed offset, heatset and long grain web offset; deviations are possible, for example with scales with picking susceptibility. Coldset newspaper printing prefers CMYK, less frequently KMCY. Reason: different ink absorbency properties of the papers and wet-in-wet ink layers.
process/separation colors couleurs de la quadrichromie the transparent printing inks CMYK in four-color printing for which color separation files/prints were produced.
Process Standard Offset Procédé standardisé offset bvdm working instruction last supplemented in 2003 and fully revised in 2012 for prepress and print production in accordance with ISO 12647-2; contains numerous notes on color management.
profile profil see ICC profile
profile connection space device-independent auxiliary color space (CIEXYZ or CIELAB) which serves to link ICC device profiles with the same or with different numbers of color channels. Since, in a CMYK-to-CMYK transformation via three-channel PCS, the information of the achromatic black channel is lost, DeviceLink technology is preferred in the interest of separation-maintaining adaptation, bypassing the PCS.
profile creation création de profil see device profile creation, (color space) targeting
profile linking liaison de profils see device profile linking/connecting (see “scenarios” box on page 84)
prog[ressive proof] épreuve de sélection sequence of color separations and their combined prints produced in press proof according to the color sequence.
proofing stock papier d’épreuvage stock specially adapted to test printing methods (inkjet print) and whose surface coloration is to simulate the subsequent use of the print run (e.g. newsprint, printing on optically brightened paper).
protanomaly protanomalie color vision deficiency; green photoreceptor weakness, red-green metamerism.
protanopia protanopie color vision deficiency, green receptor failure, red-green confusion.
psychology of colors psychologie des couleurs complex, partially inconsistent view of color perception and effects
psychometric terms termes psychométriques clear and understandable intuitive designations proposed by the CIE; these are compared with the psychophysical color attributes in order to give lay persons and test persons a vocabulary (see also box on page 86).
psychometry psychométrie visual method for determining tolerance thresholds for color comparisons; purposes: creation of perceptually equidistant color ordering systems and color spaces, determining industrial chromatic aberration tolerances;procedure: statistical evaluation of the results of a sufficiently large group of test persons with full color vision.
purity pureté spectral characteristic of a color shade which is represented by one single wavelength. The spectrum of printing inks is so wide that a lack of purity leads to a blackish drift in combined printing.
purple line, line of purples, pure purples droite des pourpres in a chromaticity chart, the connection between the two pure colors blue and red at the ends of the spectrum. The additive blend colors between the short-wave blue end (400 nm) and the long-wave red end (700 nm) are on this line.
PvD</Leonardi Munich company which declared insolvency in 2003 and which is regarded as a pioneer of device-independent reproduction; its outstanding product was the fully automatic drum scanner SpectraScan, whose filters did not have RGB but XYZ characteristics and thus created image files that could be processed with high color depth in the CIELAB color space – but because Photoshop can only process 8-bit CIELAB, only on the workstations of the company, which did not go with the trend towards open systems.
RAL-DS HLC scheme and spot-color book [Source: RAL]
pyrometer pyromètre contactless temperature measuring device which does not measure the thermal radiation but, from a distance, compares the luminescent color of the glowing mass with the brightness of a special bulb, so that the actual temperature can be read off on a calibrated galvanometer scale.