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Halftone
Halftone is the reprographic technique that simulates continuous tone, continuous-tone imagery through the use of dots, varying either in size or in spacing, thus generating a gradient-like effect.Campbell, Alastair. ''The Designer's Lexicon''. ©2000 Chronicle, San Francisco. "Halftone" can also be used to refer specifically to the image that is produced by this process. Where continuous-tone imagery contains an infinite range of colors or greys, the halftone process reduces visual reproductions to an image that is printed with only one color of ink, in dots of differing size (pulse-width modulation) or spacing (frequency modulation) or both. This reproduction relies on a basic optical illusion: when the halftone dots are small, the human eye interprets the patterned areas as if they were smooth tones. At a microscopic level, developed black-and-white photographic film also consists of only two colors, and not an infinite range of continuous tones. For details, see film grain. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CMYK Color Model
The CMYK color model (also known as process color, or four color) is a subtractive color model, based on the CMY color model, used in color printing, and is also used to describe the printing process itself. The abbreviation ''CMYK'' refers to the four ink plates used: cyan, magenta, yellow, and key (most often black). The CMYK model works by partially or entirely masking colors on a lighter, usually white, background. The ink reduces the light that would otherwise be reflected. Such a model is called ''subtractive'', as inks ''subtract'' some colors from white light; in the CMY model, white light minus red leaves cyan, white light minus green leaves magenta, and white light minus blue leaves yellow. In additive color models, such as RGB, white is the ''additive'' combination of all primary colored lights, and black is the absence of light. In the CMYK model, it is the opposite: white is the natural color of the paper or other background, and black results from a full ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CMYK Raster Print
The CMYK color model (also known as process color, or four color) is a subtractive color model, based on the CMY color model, used in color printing, and is also used to describe the printing process itself. The abbreviation ''CMYK'' refers to the four ink plates used: cyan, magenta, yellow, and key (most often black). The CMYK model works by partially or entirely masking colors on a lighter, usually white, background. The ink reduces the light that would otherwise be reflected. Such a model is called ''subtractive'', as inks ''subtract'' some colors from white light; in the CMY model, white light minus red leaves cyan, white light minus green leaves magenta, and white light minus blue leaves yellow. In additive color models, such as RGB, white is the ''additive'' combination of all primary colored lights, and black is the absence of light. In the CMYK model, it is the opposite: white is the natural color of the paper or other background, and black results from a full com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frederic Eugene Ives
Frederic Eugene Ives (February 17, 1856 – May 27, 1937) was a United States of America, U.S. inventor who was born in Litchfield, Connecticut, Litchfield, Connecticut. In 1874–78 he had charge of the photographic laboratory at Cornell University. He moved to Philadelphia, Pennsylvania, where in 1885 he was one of the founding members of the Photographic Society of Philadelphia. He was awarded the Franklin Institute's Elliott Cresson Medal in 1893, the Edward Longstreth Medal in 1903, and the The Franklin Institute Awards, John Scott Medal in 1887, 1890, 1904 and 1906. He was elected to the American Philosophical Society in 1922. His son Herbert E. Ives was a pioneer of television and telephotography, including color facsimile. Color photography Ives was a pioneer in the field of color photography. He first demonstrated a system of natural color photography at the 1885 Novelties Exposition of the Franklin Institute in Philadelphia.Louis Walton Sipley, ''A Half Century of Color ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lines Per Inch
Lines per inch (LPI) is a measurement of printing resolution. A line consists of halftones that is built up by physical ink dots made by the printer device to create different tones. Specifically LPI is a measure of how close together the lines in a halftone grid are. The quality of printer device or screen determines how high the LPI will be. High LPI indicates greater detail and sharpness. Printed magazines and newspapers often use a halftone system. Typical newsprint paper is not very dense, and has relatively high dot gain or color bleeding, so newsprint is usually around 85 LPI. Higher-quality paper, such as that used in commercial magazines, has less dot gain, and can range up to 300 LPI with quality glossy (coated) paper. In order to effectively utilize the entire range of available LPI in a halftone system, an image selected for printing generally must have 1.5 to 2 times as many samples per inch (SPI). For instance, if the target output device is capable of printin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Continuous Tone
A continuous-tone image is one in which each color at any point in the image can transition smoothly between shades, rather than being represented by discrete elements such as halftones or pixels. Examples of continuous-tone images are natural phenomena, images produced with dye-based processes, images produced with certain analog printmaking processes ( intaglio, block printing, stone lithography), and paintings. Halftone prints (as produced with inkjet and offset printers), traditional film, and digital screens are not truly continuous-tone since they rely on discrete elements (halftones, grains, or pixels) to create an image. However, the term applies when the appearance is so smooth that the breaks or gaps between tonal values are imperceptible. TV, computer and phone displays are effectively continuous. Purely analog video signals can provide infinite tone variations according to their gamut. See also *Halftone Halftone is the reprographic technique that simulate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Woodburytype
A Woodburytype is both a printing process and the print that it produces. In technical terms, the process is a ''photomechanical'' rather than a ''photographic'' one, because sensitivity to light plays no role in the actual printing. The process produces very high quality continuous tone images in monochrome, with surfaces that show a slight relief effect. Essentially, a Woodburytype is a mold-produced copy of an original photographic negative with a tonal range similar to a carbon print. The process was introduced by the English photographer Walter B. Woodbury and was in use during the final third of the 19th century, most commonly for illustrating fine books with photographic portraits. It was ultimately displaced by halftone processes that produced prints of lower quality but were much cheaper. Process A dichromate-sensitized sheet of gelatin is exposed to UV-rich light through a photographic negative, causing each area of the gelatin to harden to a depth proportional to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Color
Color (or colour in English in the Commonwealth of Nations, Commonwealth English; American and British English spelling differences#-our, -or, see spelling differences) is the visual perception based on the electromagnetic spectrum. Though color is not an inherent property of matter, color perception is related to an object's light absorption, emission spectra, emission, Reflection (physics), reflection and Transmittance, transmission. For most humans, colors are perceived in the visible light spectrum with three types of cone cells (trichromacy). Other animals may have a different number of cone cell types or have eyes sensitive to different wavelengths, such as bees that can distinguish ultraviolet, and thus have a different color sensitivity range. Animal perception of color originates from different light wavelength or spectral sensitivity in cone cell types, which is then processed by the brain. Colors have perceived properties such as hue, colorfulness (saturation), and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canadian Illustrated News
The ''Canadian Illustrated News'' was a weekly Canada, Canadian illustrated magazine published in Montreal from 1869 to 1883. It was published by George-Édouard Desbarats, George Desbarats. The magazine was notable for being the first in the world to consistently produce photographs at a successful rate. This was possible with the financial backing of George Desbarats, as well as the invention of half-tone photoengraving by William Leggo. The Canadian federal MP Fabien Vanasse was one of the notable journalists of the publication. More than 15,000 illustrations were published during the magazine's 14 years of existence, before it stopped publication as it accumulated losses. The magazine had a French language counterpart also published by Desbarats called ''L'Opinion publique'', that published many times the English magazine's illustrations and many of its articles translated into French. Many notable prints in ''Canadian Illustrated News'' are kept in various museums. For ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Posterization
Posterization or posterisation of an image is the conversion of a continuous gradation of tone to several regions of fewer tones, causing abrupt changes from one tone to another. This was originally done with photographic processes to create posters. It can now be done photographically or with digital image processing, and may be deliberate or an unintended artifact of color quantization. Posterization is often the first step in vectorization (tracing) of an image. Cause The effect may be created deliberately, or happen accidentally. For artistic effect, most image editing programs provide a posterization feature, or photographic processes may be used. Unwanted posterization, also known as banding, may occur when the color depth, sometimes called bit depth, is insufficient to accurately sample a continuous gradation of color tone. As a result, a continuous gradient appears as a series of discrete steps or bands of color — hence the name. When discussing fixed pixel displ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contrast (vision)
Contrast is the difference in luminance or color that makes an object (or its representation in an image or display) visible against a background of different luminance or color. The human visual system is more sensitive to contrast than to absolute luminance; thus, we can perceive the world similarly despite significant changes in illumination throughout the day or across different locations. The maximum contrast of an image is termed the contrast ratio or dynamic range. In images where the contrast ratio approaches the maximum possible for the medium, there is a ''conservation of contrast''. In such cases, increasing contrast in certain parts of the image will necessarily result in a decrease in contrast elsewhere. Brightening an image increases contrast in darker areas but decreases it in brighter areas; conversely, darkening the image will have the opposite effect. Bleach bypass reduces contrast in the darkest and brightest parts of an image while enhancing luminance contr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
