|
Spectral Printing
Spectral printing is the art and science of reproducing the spectra of a scene-referred image, by means of hard-copy printing using more than four process-colour printing inks namely cyan, magenta, yellow and black and their lighter versions. The additional secondary inks are often referred to as spot colours. As opposed to normal four-colour process printing, the aim of spectral printing is to eliminate or reduce metamerism either due to illuminant or observer. A side effect of printing with more than four primary inks is that it enables an improvement in colour gamut of the printed image due to the use of secondary inks, which can be used for CCR (colour-component-replacement) similar to UCR ( under-colour-removal) or GCR ( gray-component-replacement) for black. The use of these multiple inks inflicts additional constraints in the printing system in the context of its modeling parameters such as ink-media interaction, total-ink-limit, halftoning with multiple-inks and the eff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Color Printing
Color printing or colour printing is the reproduction of an image or text in color (as opposed to simpler black and white or monochrome printing). History of color printing Woodblock printing on textiles preceded printing on paper in both East Asia and Europe, and the use of different blocks to produce patterns in color was common. The earliest way of adding color to items printed on paper was by hand-coloring, and this was widely used for printed images in both Europe and East Asia. Chinese woodcuts have this from at least the 13th century, and European ones from very shortly after their introduction in the 15th century, where it continued to be practiced, sometimes at a very skilled level, until the 19th century—elements of the official British Ordnance Survey maps were hand-colored by boys until 1875. Early European printed books often left spaces for initials, rubrics and other elements to be added by hand, just as they had been in manuscripts, and a few early printe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spot Color
In offset printing, a spot color or solid color is any color generated by an ink (pure or mixed) that is printed using a ''single run'', whereas a process color is produced by printing a series of dots of different colors. The widespread offset-printing process is composed of the four spot colors cyan, magenta, yellow, and Keyline, key (black) commonly referred to as CMYK. More advanced processes involve the use of six spot colors (Hexachrome, hexachromatic process), which add Orange (colour), orange and green to the process (termed Hexachrome, CMYKOG). The two additional spot colors are added to compensate for the ineffective reproduction of faint Tint, shade and tone, tints using CMYK colors only. However, offset technicians around the world use the term ''spot color'' to mean any color generated by a non-standard offset ink; such as Metallic color, metallic, fluorescent, or custom hand-mixed inks. When making a multi-color print with a spot color process, every spot color nee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metamerism (color)
In colorimetry, metamerism is a perceived matching of colors with different (nonmatching) spectral power distributions. Colors that match this way are called metamers. A spectral power distribution describes the proportion of total light given off (emitted, transmitted, or reflected) by a color sample at each visible wavelength; it defines the complete information about the light coming from the sample. However, the human eye contains only three color receptors (three types of cone cells), which means that all colors are reduced to three sensory quantities, called the tristimulus values. Metamerism occurs because each type of cone responds to the cumulative energy from a broad range of wavelengths, so that different combinations of light across all wavelengths can produce an equivalent receptor response and the same tristimulus values or color sensation. In color science, the set of sensory spectral sensitivity curves is numerically represented by color matching functions. Sou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamut
In color reproduction and colorimetry, a gamut, or color gamut , is a convex set containing the colors that can be accurately represented, i.e. reproduced by an output device (e.g. printer or display) or measured by an input device (e.g. camera or visual system). Devices with a larger gamut can represent more colors. Similarly, gamut may also refer to the colors within a defined color space, which is not linked to a specific device. A trichromatic gamut is often visualized as a color triangle. A less common usage defines gamut as the subset of colors contained within an image, scene or video. Introduction The term ''gamut'' was adopted from the field of music, where the medieval Latin expression "gamma ut" meant the lowest tone of the G scale and, in time, came to imply the entire range of musical notes of which musical melodies are composed. William Shakespeare, Shakespeare's use of the term in ''The Taming of the Shrew'' is sometimes attributed to the author / musician Thom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Under Color Removal
In printing, under color removal (UCR) is a process of eliminating overlapping yellow, magenta, and cyan that would have added to a dark neutral (black) and leaving the black ink only, called a ''full black'', during the color separation process. Under color removal is used in '' process color'' printing. Black ink used to add details and darkness in shadowed areas is called a ''skeletal black''. With current ink technology, the total CMYK ink in the shadows refuses to stick after it reaches the dark shadows (usually above a 250% total CMYK coverage), and begins to peel off. To prevent this, printers developed UCR, in which neutral shadowswhich would have normally been produced by overprinting the four inks ''cyan'', ''magenta'', ''yellow'' and ''black'' on top of each other (high ink coverage)are replaced with the single layer of ''black''. UCR removes the color inks ''under'' the black, resulting in a single layer of ink which sticks to the sheet better, and saves on the consum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grey Component Replacement
Within the CMY color space used in color printing, a range of colors can be achieved by combining the three primary colors. This combination can be thought of as a hue component (which will require a maximum of two primary colors) and a grey component (a mixture of all three, in an appropriate quantity to give the required saturation). If the grey component is replaced by black ink, the same color is being achieved by using two primaries and black. The substitution of black for the grey component is described as grey component replacement (GCR). In GCR, contrary to under color removal (UCR), the CMY values that add to grey all along the tone scale can be replaced with black ink. UCR only adds black to the CMY equivalent of what would have printed as a grey or near-grey. Advantages * GCR uses less ink overall, and a larger proportion of the ink is black, which is normally cheaper than the others. * The areas where less ink is used are regions of high ink use, so the potential ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Art Photography Print Types
Art photography print types refers to the process and paper of how the photograph is printed and developed. * C-Print / Chromogenic Print: A C-Print is the traditional way of printing using negatives or slides, an enlarger, and photographic paper—through a process of exposure and emulsive chemical layers. Chromogenic color prints are composed of cyan, magenta, and yellow layers, which together create the complete image. This process is the most common type of color photo printing. * Digital C-Print: Also called Lambda or Lightjet prints, this process uses digital exposure systems to output the image, but traditional photographic paper and emulsion processes to produce the final print. * Inkjet Print: Inkjet is a broad category for works printed through an additive process of sprayed ink droplets, as opposed to being chemically developed. Essentially, it is a higher quality version of a household printer. There are several types of inkjet prints, including dye- and pigment-based t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
