There are two main types of computer graphics - raster (composed of pixels) and vector (composed of paths). Raster images are better known as bitmaps and are made up of grids of pixels, while vector graphics use mathematical relationships between points and paths. Bitmaps appear jagged when enlarged but vectors remain smooth at any size. Anti-aliasing can make bitmaps appear smoother by applying transitions between pixels. Resolution refers to the number of pixels per inch, with higher resolution creating better quality images. Aspect ratio describes the width to height ratio of an image. File formats encode information for storage and there are different formats for different types of files and information.
2. HA1 - Technical File – Raster and Vector Images There are two kinds of computer graphics - raster (composed of pixels) and vector (composed of paths). Raster images are more commonly called bitmap images. A bitmap image uses a grid of individual pixels where each pixel can be a different colour or shade. Bitmaps are composed of pixels. Vector graphics use mathematical relationships between points and the paths connecting them to describe an image. Vector graphics are composed of paths. Raster Vector The larger you display a bitmap, the more jagged it appears, while a vector image remains smooth at any size. The jagged appearance of bitmap images can be partially overcome with the use of "anti-aliasing". Anti-aliasing is the application of subtle transitions in the pixels along the edges of images to minimize the jagged effect . A scalable vector image will always appear smooth . Anti-Aliased Bitmap Image: Smooth Vector Image:
3. Bitmap images require higher resolutions and anti-aliasing for a smooth appearance. Vector-based graphics on the other hand are mathematically described and appear smooth at any size or resolution. Bitmaps are best used for photographs and images with subtle shading. Graphics best suited for the vector format are page layout, type, line art or illustrations.
4. HA1 - Technical File – Antialiasing Anti-Aliasing is a method of fooling the eye that a jagged edge is really smooth. Anti-Aliasing is often referred in games and on graphics cards. In games especially the chance to smooth edges of the images goes a long way to creating a realistic 3D image on the screen. Anti-Aliasing does not actually smooth any edges of images it merely fools the eye. Blown up letter a with no anti-aliasing: Had anti-aliasing applied: You can still tell that the letter of the left is jagged but the letter on the right looks a lot smoother and less blurry than the example above. The image has been shrunk down back to normal size. Anti-Aliasing brings a much more pleasing image to the eye. Something like what comes out of a high class printer rather than what you can be used to seeing when on a computer screen.
5. HA1 - Technical File – Resolution Resolution is the number of pixels in a linear inch—pixels per inch (or PPI), but it is most commonly referred to as dots per inch (DPI). The more pixels, or “dots,” per inch, the higher your image resolution will be. With colour images, each pixel can be one of 16 million different colours. For black and white images, there are 256 gradations of gray pixels ranging from black to white: 0 (black) through 255 (white). More pixels means higher resolution, which creates better image quality because you end up with more realistic representations of colour, better gradations of both individual colours and gray tones, and crisper images in general.
6. HA1 - Technical File – 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, if the width is divided into x units of equal length and the height is measured using this same length unit, the height will be measured to be y units. For example, consider a group of images, all with an aspect ratio of 16:9. One image is 16 inches wide and 9 inches high. Another image is 16 centimetres wide and 9 centimetres high. A third is 8 yards wide and 4.5 yards high.
7. HA1 - Technical File – File Formats 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 can be divided into proprietary and open formats.
8. HA1 - Technical File – Colour Models A colour model is an abstract mathematical model describing the way colours can be represented as tuples of numbers, typically as three or four values or colour 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 colours is called colour space. This section describes ways in which human colour vision can be modelled.
9. HA1 - Technical File – Adobe Photoshop 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. Alongside Photoshop and Photoshop Extended, Adobe also publishes Photoshop Elements and Photoshop Light room, collectively called "The Adobe Photoshop Family". In 2008, Adobe released Adobe Photoshop Express, a free web-based image editing tool to edit photos directly on blogs and social networking sites; in 2011 a version was released for the Android operating system and the iphone.
10. HA1 - Technical File – Adobe Illustrator Sophisticated vector drawing tools Create distinctive designs with precise shape-building tools, fluid and painterly brushes, and advanced path controls. Beautiful Strokes Fully control variable-width strokes, arrowheads, dashes, and art brush scaling along a path. Perspective drawing Use perspective grids to draw shapes and scenes in accurate 1-, 2-, or 3-point linear perspective, creating the look of realistic depth and distance. Bristle Brush Paint with vectors that resemble real-world brush strokes. Achieve the expressiveness of natural media with the scalability of vector graphics. 3D effects Turn 2D shapes into fully editable 3D objects by extruding and revolving paths. Add lighting and wrap images around 3D shapes to easily create objects such as packaging mock-ups, and separate spot colours applied to 3D artwork. Clipping masks Use clipping masks to hide areas of an object or group, crop placed images, or cut intricate shapes. Quickly find the clipping mask options in the Control panel and work with masks more easily, thanks to new viewing choices for both masks and masked objects.
11. HA1 - Technical File – Adobe InDesign 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 Design 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.
