Graphic File Format notes

File Formats
~All computer files are packaged in different formats, which is determined by file origin
~Ai & Psd are raw uncompressed files
  - must be compressed to share on the internet
Compression
~Ai & Psd are raw uncompressed files
  - must be compressed to share on the internet
~Commonly used compression file types include JPG, PNG, GIF, TIFF, etc.
  -built for certain types of images, may lower size or quality
  -make sure to use right format choice to prevent this from happening
  - each compression format has it's advantages and disadvantages
Lossy vs Lossless
~Graphic image formats fall under two catagories of compression, Lossy & Lossless
~Lossy image data is lost or reduced for smaller file sizes due to poor image quality
  -"compression artifact"
  - generation loss = when a file is compressed multiple times
  -ex. JPGs with flat colour
~Lossless regains image data for larger file sizes and higher quality
  -Ex. PNG
TIF format
~"Tagged Image Format"
~Common format for desktop publishing, print, photo and graphic design
~Lossless file format
~Larger file sizes, unfit for internet display or browser compatible
JPG format
~"Joint Photographers Expert Group"
~Created for digital photography and works best with photographic content
~Lossy format
~Can reduce an image by 10:1 without showing significant compression artifacts
~Adjustable compression levels
GIF format
~"Graphics Interchange Format"
~Best for images with flat colour or tone, like a cartoon
~Reduces image size by "indexing" colour from 3 channels to 1
~Adjusts by changing colour bit levels from 1 to 8
~No DPI (Dots per Inch) data for printing -- unfit for printing
KNOW YOUR PIXELS ~
~2 Types of pixels; contiguous or non contiguous
~TIF and JPG  are best for images with pixels that blend in colour, or "contiguous pixels"
~GIF is best for images with flat, even tone, or "non-contiguous pixels"
Alias vs. Anti-Alias
~Alias preserves pixel, while Anti-Alias created gradients to create "smooth" lines