Computer Science 1033A/B Lecture Notes - Lecture 4: Lossless Compression, Dither, Gif

• School: Western University
• Department: Computer Science
• Course: Computer Science 1033A/B
• Professor: Laura Reid

Document Summary

Optimize image: alter file size but keep quality. Colour resolution (bit depth): # colours used (8 bit, 16, 24,) Gif (graphics interchange format): cross platform (works on macs, windows, supports 8 bit colour scheme max (max 256 colours) Juxtaposing pixels of two colours to create the illusion that a third colour is present (grainy look) Reduce the number of colours in a gif and choose options to control the way colours dither in the application or in a browser. Most common option of jpeg gif. If an image uses colours outside of browser safe pallet, browser auto dithers into safe. Browser safe pallet: 216 colors honored between browsers, operating systems and computer platforms. Lets you have a feel for the whole picture, without downloading the image. A process by which the image is drawn in a series of passes rather than all at the same time. Good when image file sizes are really big.