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Feathering is a technique used in computer graphics software to smooth or blur the edges of a feature. The term is inherited from a technique of fine retouching using fine feathers.
Feathering is most commonly used on a paintbrush tool in computer graphics software. This form of feathering makes the painted area appear smooth. It may give the effect of an airbrush or spraypaint. Color is concentrated at the center of the brush area, and it blends out toward the edges.
Feathering is not only used on paintbrushes in computer graphics software. Feathering may also blend the edges of a selected feature into the background of the image. When composing an image from pieces of other images, feathering helps make added features look "in place" with the background image. For instance, if someone were to want to add a leaf to a photograph of grass using computer graphics software, he or she might use feathering on the leaf to make it blend in with the grassy background.
The "Clone" tool is very important in photograph manipulation on computer graphics software. The clone tool is used to actively copy and offset pixels from one area of an image to another while the artist moves the clone tool around the area to be copied. A good example is the use of the clone tool to cover a skin blemish by copying skin from one area of an image and placing it over the blemish. An important aspect of making a clone tool blend well in an image is to use feathering on the clone tool. This makes the pixels being copied have more effect on the area they are copied to closer to where the artist is dragging his or her mouse or stylus, and makes the pixels have less effect the farther they are from the clone tool (and where the artist is using it). Thus, with the skin example, skin pixels copied directly over the blemish will have strong effect on the blemish, thus hiding it, but skin pixels copied to the area around the blemish will not affect this area much, and will keep the natural look of the skin (wrinkles etc.) intact as much as possible.
In computer graphics, alpha compositing or alpha blending is the process of combining one image with a background to create the appearance of partial or full transparency. It is often useful to render picture elements (pixels) in separate passes or layers and then combine the resulting 2D images into a single, final image called the composite. Compositing is used extensively in film when combining computer-rendered image elements with live footage. Alpha blending is also used in 2D computer graphics to put rasterized foreground elements over a background.
In digital signal processing, spatial anti-aliasing is a technique for minimizing the distortion artifacts (aliasing) when representing a high-resolution image at a lower resolution. Anti-aliasing is used in digital photography, computer graphics, digital audio, and many other applications.
Bit blit is a data operation commonly used in computer graphics in which several bitmaps are combined into one using a boolean function.
Shading refers to the depiction of depth perception in 3D models or illustrations by varying the level of darkness. Shading tries to approximate local behavior of light on the object's surface and is not to be confused with techniques of adding shadows, such as shadow mapping or shadow volumes, which fall under global behavior of light.
Deluxe Paint, often referred to as DPaint, is a bitmap graphics editor created by Dan Silva for Electronic Arts and published for the then-new Amiga 1000 in November 1985. A series of updated versions followed, some of which were ported to other platforms. An MS-DOS release with support for the 256 color VGA standard became popular for creating pixel graphics in video games in the 1990s.
Ray casting is the methodological basis for 3D CAD/CAM solid modeling and image rendering. It is essentially the same as ray tracing for computer graphics where virtual light rays are "cast" or "traced" on their path from the focal point of a camera through each pixel in the camera sensor to determine what is visible along the ray in the 3D scene. The term "Ray Casting" was introduced by Scott Roth while at the General Motors Research Labs from 1978–1980. His paper, "Ray Casting for Modeling Solids", describes modeled solid objects by combining primitive solids, such as blocks and cylinders, using the set operators union (+), intersection (&), and difference (-). The general idea of using these binary operators for solid modeling is largely due to Voelcker and Requicha's geometric modelling group at the University of Rochester. See Solid modeling for a broad overview of solid modeling methods. This figure on the right shows a U-Joint modeled from cylinders and blocks in a binary tree using Roth's ray casting system, circa 1979.
Transparency in computer graphics is possible in a number of file formats. The term "transparency" is used in various ways by different people, but at its simplest there is "full transparency" i.e. something that is completely invisible. Only part of a graphic should be fully transparent, or there would be nothing to see. More complex is "partial transparency" or "translucency" where the effect is achieved that a graphic is partially transparent in the same way as colored glass. Since ultimately a printed page or computer or television screen can only be one color at a point, partial transparency is always simulated at some level by mixing colors. There are many different ways to mix colors, so in some cases transparency is ambiguous.
Attribute clash is a display artifact caused by limits in the graphics circuitry of some colour 8-bit home computers, most notably the ZX Spectrum, where it meant that only two colours could be used in any 8×8 tile of pixels. The effect was also noticeable on MSX software and in some Commodore 64 titles. Workarounds to prevent this limit from becoming apparent have since been considered an element of Spectrum programmer culture.
Digital illustration or computer illustration is the use of digital tools to produce images under the direct manipulation of the artist, usually through a pointing device such as a graphics tablet or, less commonly, a mouse. It is distinguished from computer-generated art, which is produced by a computer using mathematical models created by the artist. It is also distinct from digital manipulation of photographs, in that it is an original construction "from scratch". Photographic elements such as background or texture may be incorporated into such works, but they are not necessarily the primary basis.
Compositing is the process or technique of combining visual elements from separate sources into single images, often to create the illusion that all those elements are parts of the same scene. Live-action shooting for compositing is variously called "chroma key", "blue screen", "green screen" and other names. Today, most, though not all, compositing is achieved through digital image manipulation. Pre-digital compositing techniques, however, go back as far as the trick films of Georges Méliès in the late 19th century, and some are still in use.
In computer graphics, pixelation is caused by displaying a bitmap or a section of a bitmap at such a large size that individual pixels, small single-colored square display elements that comprise the bitmap, are visible. Such an image is said to be pixelated.
Texture synthesis is the process of algorithmically constructing a large digital image from a small digital sample image by taking advantage of its structural content. It is an object of research in computer graphics and is used in many fields, amongst others digital image editing, 3D computer graphics and post-production of films.
The clone tool, as it is known in Adobe Photoshop, Inkscape, GIMP, and Corel PhotoPaint, is used in digital image editing to replace information for one part of a picture with information from another part. In other image editing software, its equivalent is sometimes called a rubber stamp tool or a clone brush.
Mattes are used in photography and special effects filmmaking to combine two or more image elements into a single, final image. Usually, mattes are used to combine a foreground image with a background image. In this case, the matte is the background painting. In film and stage, mattes can be physically huge sections of painted canvas, portraying large scenic expanses of landscapes.
Helicon Filter, also referred to as Helicon, Filter, or as HF, was a proprietary commercial and shareware photo editing software program for Microsoft Windows, similar to such programs as Adobe Photoshop and GIMP, developed and published by Helicon Soft Ltd. Unlike these other programs, Helicon Filter is designed primarily to edit and improve existing photos and not for graphics creation. Helicon Filter's interface also differs from other programs in that compact toolbars and menus containing editing tools are replaced with labeled "filter" tabs, each tab containing labeled edit options specific to a single aspect of the picture. Although some editors used to Photoshop-style programs may initially find this layout unfamiliar and unlike the standard toolbar layout, beginners and those who don't recognize the standard icons generally find this very helpful for getting through the editing process.
Image editing encompasses the processes of altering images, whether they are digital photographs, traditional photo-chemical photographs, or illustrations. Traditional analog image editing is known as photo retouching, using tools such as an airbrush to modify photographs or editing illustrations with any traditional art medium. Graphic software programs, which can be broadly grouped into vector graphics editors, raster graphics editors, and 3D modelers, are the primary tools with which a user may manipulate, enhance, and transform images. Many image editing programs are also used to render or create computer art from scratch. The term "image editing" usually refers only to the editing of 2D images, not 3D ones.
Paintbrush is a raster image editor for Mac OS X. It aims to replace MacPaint, an image editor for the classic Mac OS last released in 1988. It also is an alternative to MS Paint. It has basic raster image editing capabilities and a simple interface designed for ease of use. It exports as PNG, JPG, BMP, GIF, and TIFF. The application also is often used for pixel art because of its grid option, and is not made for large scale images or GIMP or Photoshop-like editing on pictures or photographs.
Composite artifact colors is a designation commonly used to address several graphic modes of some 1970s and 1980s home computers. With some machines, when connected to an NTSC TV or monitor over composite video outputs, the video signal encoding allowed for extra colors to be displayed, by manipulating the pixel position on screen, not being limited by each machine's hardware color palette.
Video matting is a technique for separating the video into two or more layers, usually foreground and background, and generating alpha mattes which determine blending of the layers. The technique is very popular in video editing because it allows to substitute the background, or process the layers individually.
Retouch4me is a family of artificial intelligence-powered plug-ins for photography and video retouching, compatible with Adobe Photoshop; Adobe Lightroom, and Capture One.