|
Dot Etching
Halftone is the reprographic technique that simulates 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. Just as color p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halftoning Introduction
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] |
Intaglio (printmaking)
Intaglio ( ; ) is the family of printing and printmaking techniques in which the image is incised into a surface and the incised line or sunken area holds the ink. It is the direct opposite of a relief print where the parts of the matrix that make the image stand ''above'' the main surface. Normally copper, or in recent times zinc, sheets called plates are used as a surface or matrix, and the incisions are created by etching, engraving, drypoint, aquatint or mezzotint, often in combination. Collagraphs may also be printed as intaglio plates. After the decline of the main relief technique of woodcut around 1550, the intaglio techniques dominated both artistic printmaking as well as most types of illustration and popular prints until the mid 19th century. The word "intaglio" describes prints created from plates where the ink-bearing regions are recessed beneath the plate's surface. Though brass, zinc, and other materials are occasionally utilized, copper is the most commo ... [...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] |
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] |
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] |
Ronchi Ruling
A Ronchi ruling, Ronchi grating, or Ronchi mask, named after the Italian physicist Vasco Ronchi, is a constant-interval bar and space square-wave optical target or mask. The design produces a precisely patterned light source by reflection or illumination, or a stop pattern by transmission, with precise uniformity, spatial frequency, sharp edge definition, and high contrast ratio. Manufacturing Ronchi rulings are typically manufactured through photolithographic deposition of metallic chromium on a substrate, which yields a precise, nearly 100% contrast pattern. For a reflective or illuminated type, dark stripes are printed on a diffusely reflecting or translucent substrate, such as a square of white ceramic material or opal glass. For a transmissive type, opaque stripes are printed on a transparent glass substrate. A transmissive type may be readily modified to act as an illuminated type by stacking a reflective object behind it. Applications A test target in the Ronchi patt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffraction
Diffraction is the deviation of waves from straight-line propagation without any change in their energy due to an obstacle or through an aperture. The diffracting object or aperture effectively becomes a secondary source of the Wave propagation, propagating wave. Diffraction is the same physical effect as Wave interference, interference, but interference is typically applied to superposition of a few waves and the term diffraction is used when many waves are superposed. Italian scientist Francesco Maria Grimaldi coined the word ''diffraction'' and was the first to record accurate observations of the phenomenon in 1660 in science, 1660. In classical physics, the diffraction phenomenon is described by the Huygens–Fresnel principle that treats each point in a propagating wavefront as a collection of individual spherical wavelets. The characteristic pattern is most pronounced when a wave from a Coherence (physics), coherent source (such as a laser) encounters a slit/aperture tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithography
Lithography () is a planographic method of printing originally based on the miscibility, immiscibility of oil and water. The printing is from a stone (lithographic limestone) or a metal plate with a smooth surface. It was invented in 1796 by the German author and actor Alois Senefelder and was initially used mostly for sheet music, musical scores and maps.Meggs, Philip B. ''A History of Graphic Design''. (1998) John Wiley & Sons, Inc. p 146, .Carter, Rob, Ben Day, Philip Meggs. ''Typographic Design: Form and Communication'', Third Edition. (2002) John Wiley & Sons, Inc. p. 11. Lithography can be used to print text or images onto paper or other suitable material. A lithograph is something printed by lithography, but this term is only used for printmaking, fine art prints and some other, mostly older, types of printed matter, not for those made by modern commercial lithography. Traditionally, the image to be printed was drawn with a greasy substance, such as oil, fat, or wax on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relief Printing
Relief printing is a family of printing methods where a printing block, plate or matrix (printing), matrix, which has had ink applied to its non-recessed surface, is brought into contact with paper. The non-recessed surface will leave ink on the paper, whereas the recessed areas will not. A printing press may not be needed, as the back of the paper can be rubbed or pressed by hand with a simple tool such as a brayer or roller. In contrast, in Intaglio (printmaking), intaglio printing, the ''recessed'' areas are printed. Relief printing is one of the traditional families of printmaking techniques, along with the Intaglio (printmaking), intaglio and planographic printing, planographic families, though modern developments have created others. The relief family of techniques In the relief family of printing, the matrix was historically made Subtractive manufacturing, subtractively, by removing material from the surface of areas not intended to be printed. The remaining surface wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philadelphia
Philadelphia ( ), colloquially referred to as Philly, is the List of municipalities in Pennsylvania, most populous city in the U.S. state of Pennsylvania and the List of United States cities by population, sixth-most populous city in the United States, with a population of 1,603,797 in the 2020 United States census, 2020 census. The city is the urban core of the Philadelphia metropolitan area (sometimes called the Delaware Valley), the nation's Metropolitan statistical area, seventh-largest metropolitan area and ninth-largest combined statistical area with 6.245 million residents and 7.379 million residents, respectively. Philadelphia was founded in 1682 by William Penn, an English Americans, English Quakers, Quaker and advocate of Freedom of religion, religious freedom, and served as the capital of the Colonial history of the United States, colonial era Province of Pennsylvania. It then played a historic and vital role during the American Revolution and American Revolutionary ... [...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] |
