Hajid Hussain 13B-It1 Monday, 16 April 2018
Unit 30- Digital Graphics
Task 2- File Formats
In this task I have been asked to explain the different types of graphic images and how they relate to file formats. Then I must discuss the impact that file format, compression, resolution, and colour depth have on file size and image quality.
Bitmap- Let me begin with explaining on how different types of graphic images relate to file formats and starting it off with bitmap. Bitmap images are stored as pixels. Each pixel within the image must have a colour value which is stored and makes up the file size. The physical size of the bitmap influences the file size of the graphic, for example, a 200 by 200 file will always have a file size of 118Kb. When increasing the size of a bitmap, additional pixels need to be added, which then loses the quality of the graphic, also known as pixilation.
JPEG- There are also JPEGs. The JPEG stands for Joint Photographic Experts Group. JPEG acts as a lossy compression for bitmap at a ratio of 10:1 in file sizes. JPEGs are also stored as pixels. JPEG file formats compresses file sizes by looking at each pixel and the colours around that pixel. If they are similar, the pixel spans across them pixel so 3 pixels with the same colour could become one pixel. This then decreases the file size as less information needs to be stored. However, the quality of the image is lost as previous colours of the original image could be replaced by pixels due to the similarity of colour. JPEGs are used in digital photography manipulation.
GIF- GIF stands for Graphical Interchange Format. This format has an 8-bit colour depth rather than the 24-bit of a JPEG, which consists no more than of 256 colour combinations. For this reason, GIF is not really used for photographic manipulation as a picture could cover a lot of different contrasts of colour. GIF’s can be used for animation and creating images, this then allows transparency within graphics.
Vector Graphics- Vector graphics don’t use pixels, rather vector graphics use mathematical formulas and store these formulas to makeup the file size. The formula allows the image to be resized and not lose the quality of the graphic. The more formulas that need to be processed, the bigger the file size is so complex vector graphics will have a large file size than bitmaps due to the amount of formulas stored within that one file. Vector graphics are used for logos as they can be put on things from letters to a side of the bus.
SVG- SVG stands for Scalable Vector Graphics. SVG files can either be animated or static depending on the graphic behaviours. SVR behaviour is defined within an Extendable Markup Language, also known as XML, text file. You can use text editor software to create your graphic. However, it is simpler to practically make the image. The SVG is a type of lossless compression with the file being called SVGZ which decreases the original size by 20 to 50%.
File Conversion- File convers...