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Importation d'un nuancier dans un RIP
Vous utilisez des tons directs dans vos impressions et vous souhaitez uniformiser les couleurs entre chacunes des différentes solutions d'impression de votre atelier ?Vous souhaitez synchroniser les tons directs entre les logiciels des designers et vos RIPs po...
La synthèse additive
Le principe de la synthèse additive des couleurs consiste à s'éfforcer de reconstituer, pour l'oeil humain, l'équivalent (l'apparence) de toute couleur visible, par l'addition de lumière provenant de trois sources monochromatiques rouge, verte, bleue. Un peu ...
La synthèse soustractive
Dans la synthèse soustractive tout est inversé par rapport au système additif. Le cyan, le magenta et le jaune deviennent les couleurs primaires Le rouge est la couleur complémentaire du cyan Le vert est la couleur complémentaire du magenta Le bleu est la ...
Les méthodes de rendu
Il n'est pas rare que les images issues des périphériques de capture tel que les APNs ou les scanners produisent des images dont toutes les couleurs ne peuvent pas être reproduites fidèlement sur une imprimante. La question que nous pouvons nous poser est : C...
Les instruments de mesure
Chacun de ces instruments de mesure ont un rôle bien précis, afin de les différencier, nous allons vous en faire une brève description. Spectrophotomètre Colorimètre Spectrodensitomètre Densitomètre Spectrophotomètre automatique Spectrophotomètre...
Table of prerequisites
Coraye training In order to master the use of the software, it is necessary to acquire certain notions on color management and the various functions of Coraye. To help you, we have created a table listing, by module, the skills you should have acquired. Basi...
The light + the eye = the color
Color definition Color is our perception of the different wavelengths that make up visible light. This set of wavelengths called the spectrum of light ranges from violet (wavelength = 380 nanometers) to red (wavelength = 720 nanometers). Beyond these waveleng...
Additive synthesis
The principle of additive color synthesis consists in striving to reconstitute, for the human eye, the equivalent (appearance) of any visible color, by the addition of light from three monochromatic sources red, green, blue. A little theory Additive synthesi...
Subtractive synthesis
In the subtractive synthesis everything is reversed with respect to the additive system. Cyan, magenta and yellow become the primary colors Red is the complementary color of cyan Green is the complementary color of magenta Blue is the complementary color o...
Standard and Observer illuminants
Generally speaking, the perception of the color of an object involves three elements: the light source, the object itself and the observer. The spectrum of light To fully understand how each other plays a role in perceived color, let's follow the transformat...
Independent color modes: Lab, Lch, XYZ
There are several possibilities to code the color We saw previously the RGB and the CMYK which are coded according to scales going:From 0 to 255 for the RGB (8 bits)From 0 to 100 for the CMYK (% of ink)From 000000 to FFFFFF The hexadecimal for the Web (RGB) ...
ICC Profiles
An ICC ( International Color Consortium ) profile is a file with an .icc or .icm extension. This file contains the data to convert colors from a source color space (CMYK, RGB and usually linked to a device) to an independent color space (L * a * b * or XYZ, ...
The Gamut
The gamut represents the 3-dimensional modeling of the colors of an ICC profile or an image. Usually this graphic representation is displayed in a 3D Lab space. In the example below, we can compare the gamut of the ICC profile of an Epson SC-P7000 printer wi...
Reference color spaces
As in any field, when it comes to calibration, we must always perform calibrations against a reference or a standard.The graphic chain is no exception to the rule. This is why it is necessary to use reference color spaces to standardize the colorimetric render...
The dependent color modes: RGB, CMYK
In the previous chapter we compared the gamut of different RGB profiles and we saw that each of them are able to reproduce more or less saturated colors. RGB mode Take for example the RGB sRGB and Adobe RGB 1998 profiles and compare them in the gamut Viewer:...
The Delta E
The Delta E quantifies the difference in color between two samples This value is the difference between two colors designated as two points in the Lab color space.The closer the Delta E value tends to 0, the greater the color accuracy. Using the Delta E allo...
Rendering methods
It is not uncommon for images from capture devices such as digital cameras or scanners to produce images in which all colors cannot be faithfully reproduced on a printer. The question we can ask ourselves is: How will the colors that come out of the printer's...
Spectral values
As we saw in the first chapter on light + eye = color, The eye collects information about electromagnetic frequencies, and the translation of these radiations by the brain is the sensation of color.Let's take a closer look at the visible spectrum. Monochro...
Measuring instruments
Each of these measuring instruments have a specific role, in order to differentiate them, we will give you a brief description. Spectrophotometer Colorimeter Spectrodensitometer Densitometer Automatic spectrophotometer Sphere spectrophotometer ...
M0, M1, M2, M3 modes
Fluorescent effect of optical brighteners Optical brighteners (or OBA for Optical Brightening Agent) are components added to the print medium to make them appear “whiter than white”. The principle is quite similar to that of bluing additives in detergents. OB...