HA1 - Technical File – Raster Images In computer graphics, a raster graphics image, or bitmap, is a data structure representing a generally rectangular grid of pixels, or points of colour, viewable via a monitor, paper, or other display medium. Raster images are stored in image files with varying formats (see Comparison of graphics file formats). A bitmap corresponds bit-for-bit with an image displayed on a screen, generally in the same format used for storage in the display's video memory, or maybe as a device-independent bitmap. A bitmap is technically characterized by the width and height of the image in pixels and by the number of bits per pixel (a colour depth, which determines the number of colours it can represent).
HA1 - Technical File – Vector Images Vector graphics is the use of geometrical primitives such as points, lines, curves, and shapes or polygon(s), which are all based on mathematical equations, to represent images in computer graphics. Vector graphics formats are complementary to raster graphics, which is the representation of images as an array of pixels, as is typically used for the representation of photographic images. Vector graphics are stored as mathematical expressions as opposed to bit mapped graphics which are stored as a series of mapped 'dots', also known as pixels (Picture cells). There are instances when working with vector tools and formats is the best practice, and instances when working with raster tools and formats is the best practice. There are times when both formats come together. An understanding of the advantages and limitations of each technology and the relationship between them is most likely to result in efficient and effective use of tools.
In digital signal processing, spatial anti-aliasing is the technique of minimizing the distortion artefacts known as 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. Anti-aliasing means removing signal components that have a higher frequency than is able to be properly resolved by the recording (or sampling) device. This removal is done before (re)sampling at a lower resolution. When sampling is performed without removing this part of the signal, it causes undesirable artefacts such as the black-and-white noise near the top of figure 1-a below. In signal acquisition and audio, anti-aliasing is often done using an analogy anti-aliasing filter to remove the out-of-band component of the input signal prior to sampling with an analogy-to-digital converter. In digital photography, optical anti-aliasing filters are made of birefringent materials, and smooth the signal in the spatial optical domain. The anti-aliasing filter essentially blurs the image slightly in order to reduce resolution to below the limit of the digital sensor (the larger the pixel pitch, the lower the achievable resolution at the sensor level).
In digital audio, bit depth describes the number of bits of information recorded for each sample. Bit depth directly corresponds to the resolution of each sample in a set of digital audio data. Common examples of bit depth include CD quality audio, which is recorded at 16 bits, and DVD-Audio, which can support up to 24-bit audio. A set of digital audio samples contains data that, when converted into an analogy signal, provides the necessary information to reproduce the sound wave. In pulse-code modulation (PCM) sampling, the bit depth will limit signal-to-noise ratio (S/N). The bit depth will not limit frequency range, which is limited by the sample rate.
The aspect ratio of a shape is the ratio of its longer dimension to its shorter dimension. It may be applied to two characteristic dimensions of a three-dimensional shape, such as the ratio of the longest and shortest axis, or for symmetrical objects that are described by just two measurements, such as the length and diameter of a rod. The aspect ratio of a torus is the ratio of the major axis R to the minor axis r .
A file format is a particular way that information is encoded for storage in a computer file. Since a disk drive, or indeed any computer storage, can store only bits, the computer must have some way of converting information to 0s and 1s and vice-versa. There are different kinds of formats for different kinds of information. Within any format type, e.g., word processor documents, there will typically be several different formats. Sometimes these formats compete with each other. File formats are divided into proprietary and open formats.
A color model is an abstract mathematical model describing the way colours can be represented as tuples of numbers, typically as three or four values or color components. When this model is associated with a precise description of how the components are to be interpreted (viewing conditions, etc.), the resulting set of colors is called color space. This section describes ways in which human color vision can be modeled . There are various types of color systems that classify color and analyse their effects. The American Munsell color system devised by Albert H. Munsell is a famous classification that organises various colors into a color solid based on hue, saturation and value. Other important color systems include the Swedish Natural Color System (NCS) from the Scandinavian Color Institute, the Optical Society of America's Uniform Color Space (OSA-UCS), and the Hungarian Coloroid system developed by Antal Nemcsics from the Budapest University of Technology and Economics. Of those, the NCS is based on the opponent-process color model, while the Munsell, the OSA-UCS and the Coloroid attempt to model color uniformity. The American Pantone and the German RAL commercial color-matching systems differ from the previous ones in that their color spaces are not based on an underlying color model.
Adobe Photoshop is a graphics editing program developed and published by Adobe Systems Incorporated. Adobe's 2003 "Creative Suite" rebranding led to Adobe Photoshop 8's renaming to Adobe Photoshop CS. Thus, Adobe Photoshop CS5 is the 12th major release of Adobe Photoshop. The CS rebranding also resulted in Adobe offering numerous software packages containing multiple Adobe programs for a reduced price. Adobe Photoshop is released in two editions: Adobe Photoshop, and Adobe Photoshop Extended, with the Extended having extra 3D image creation, motion graphics editing, and advanced image analysis features. Adobe Photoshop Extended is included in all of Adobe's Creative Suite offerings except Design Standard, which includes the Adobe Photoshop edition.
Adobe Illustrator is a vector graphics editor developed and marketed by Adobe Systems. Illustrator is similar in scope, intended market, and functionality to its competitors, CorelDraw and Macromedia FreeHand. Starting with version 1.0, Adobe chose to license an image of Sadra Botticelli's "The Birth of Venus" from the Bettmann Archive and use the portion containing Venus' face as Illustrator's branding image. Warnock desired a Renaissance image to evoke his vision of Postscript as a new Renaissance in publishing, and Adobe employee Luanne Seymour Cohen, who was responsible for the early marketing material, found Venus' flowing tresses a perfect vehicle for demonstrating Illustrator's strength in tracing smooth curves over bitmap source images. Over the years the rendition of this image on Illustrator's splash screen and packaging became more stylized to reflect features added in each version.
Adobe In Design is a software application produced by Adobe Systems. It can be used to create works such as posters, flyers, brochures, magazines, newspapers and books. In conjunction with Adobe Digital Publishing Suite In designing can publish content suitable for tablet devices. Graphic designers and production artists are the principal users, creating and laying out periodical publications, posters, and print media. It also supports export to EPUB and SWF formats to create digital publications, and content suitable for consumption on tablet computer devices. The Adobe In Copy word processor uses the same formatting engine as In Design.