4. HA1 - Technical File – Raster images. A raster image, also called a bitmap is a way to represent digital images. The raster image takes a wide variety of formats. A raster image represents an image in a series of bits of information which translate into pixels on the screen. These pixels form points of colour which create an overall finished image. When a raster image is created the image on the screen is converted into pixels and each pixel is assigned a specific value which determines its colour. When a raster image is viewed, the pixels usually smooth out visually for the user who sees a photograph or drawing, when blown up the pixels in a raster image become apparent. Depending on resolution, some raster images can be enlarged to very large sizes, while others quickly become difficult to see. The smaller the resolution, the smaller the digital image file, for this reason people who work with computer graphics must find a balance between resolution and image size. Resolution refers to the number of pixels per inch (PPI) or dots per inch (DPI) in the image. The higher the resolution the greater the number of pixels, this allows a greater radiation of colour that will translate better as the image is enlarged. The more pixels, the more individual points of data to be stored, as well. For high quality photography, a high DPI is preferred because the images will look more appealing to the viewer. For small images which do not need to be blown up, or when quality is not important, a low DPI can be used http://www.wisegeek.com/what-is-a-raster-image.htm
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7. Image Resolution Image resolution describes the detail an image holds. The term applies to raster digital images, film, images, and other different types of images. Higher resolution means more image detail. Image resolution can be measured in various ways. Basically resolution quantifies how close lines can be to each other and still be visibly removed. Resolution units can be tried to physical sizes to the overall size of the picture or to angular subtenant. Line pairs are often used instead of lines, a line pair compromises a dark line and an adjacent line. A resolution of ten lines per millimetre. Photographic lens and film resolution are most often quoted in line pairs per millimetre. Spatial Resolution: The measure of how closely lines can be resolved in an image is called spatial resolution, and it depends on properties of the system creating the image, not just the pixel resolution in pixels per inch. A classic test target used to determinate spatial resolution of imaging sensors and imaging sensors.
8. Aspect Ratio. The aspect ratio of an image is the ratio of the width of the image to its height, expressed as two numbers separated by a colon. That is for an x:y aspect ratio, no matter how big or small the image is, the width is divided into x units of equal length and the height is measured using the same length unit, the height will be measured to be y units. Aspect ratios are mathematically expressed as x:y and Xxy with the letter particularly used for pixel dimensions. Cinematographic aspect ratios are usually denoted as a decimal multiple of width vs. unit height. The most common aspect ratios used today in the presentation of films in movie theatres are 1.85:1 and 2.39:1 5 common aspect ratios:
9. File Formats A file format is a particular way in which information is encoded for storage in a computer file. Since a disk drive or any computer storage, can store only bits, the computer must have some way of converting information. There are different kind of formats for different kinds of information. Within any format type e.g., word processer documents, there will typically be several different formats although sometimes these formats compete with each other. File formats are divided into proprietary and open formats.
10. Color models. A color model is am abstract mathematical model by describing the way colours can represented as tuples of numbers, typically as three or four values or colour components. When the model is associated with a precise description of how the components are to be interpreted. CIE XYZ color space. One of the first mathematically defined color spaces is the CIE XYZ color space (also known as CIE 1931 color space), created by the International commission on Illumination in 1931. These data was measured for human observers and a 2 degree field of view. RGB Color Model Recognizing that the geometry of the RGB model is poorly aligned with the color-making attributes recognized by human vision, computer graphics researchers developed two alternate representations of RGB, HSV and HSL. HSV and HSL improve on the color cube representation of RGB by arranging colors of each hue in a radial slice, around a central axis of neutral colors which ranges from black at the bottom to white at the top. The fully saturated colors of each hue then lie in a circle, a colour wheel.
11. Adobe Photoshop Adobe photoshop is a graphics editing program developed and published by Adobe Systems incorporated. 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. Features Photoshop uses color models RGB, lab, CMYK, greyscale, binary bitmap, and duotone. Photoshop has the ability to read and write raster and vector image formats such as .EPS, .PING, .GIF, and .JPEG. Photoshop has ties with other Adobe software for media editing, animation, and authoring. Photoshop has ties with other Adobe software for media editing, animation, and authoring.
12. Adobe Illustrator Adobe Illustrator is a vector graphics editor developed and marketed Adobe Systems. Illustrator is similar in scope, intended market, and functionality to its competitors, Corel Draw and Macromedia Free Hand. Among the new features included in Illustrator CS2 were Live Trace, Live Paint, a control palette and custom workspaces. Live Trace allows for the conversion of bitmap imagery into vector art and improved upon the previous tracing abilities. Live Paint allows users more flexibility in applying color to objects, specifically those that overlap. In the same year as the CS2 release, Adobe Systems announced an agreement to acquire Macromedia in a stock swap valued at about $3.4 billion and it integrated the companies' operations, networks, and customer-care organizations shortly thereafter. Adobe now owned FreeHand along with the entire Macromedia product line and in 2007, Adobe announced that it would discontinue development and updates to the FreeHand program. Instead, Adobe would provide tools and support to ease the transition to Illustrator. Features
13. Adobe Indesign Adobe InDesign 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 InDesign 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 InDesign.
