Graphic File Format notes

Nick S

Sep 17th, 2013

Graphic Design Notes

Graphic File Format

·      Every time of Doc. You look at is saved in some sort of file (jpg, gif, etc.)

·      File size can be reduced by compressing your file

·      Can reduce a jpg to a 10:1 ratio without seeing any loss in quality

·      Lots of compression will result in loss of quality

·      Lossy format: Data is “lost” (blend similar-color pixels together into 1 color)

·      Lossless retains image data for higher quality final results (larger file size)

·      Graphic formats: TIF, JPG, GIF are the 3 most common formats for common activities such as printing, scanning, and displaying images over the internet

·      PNG is a common web format, is high quality and can contain an alpha (transparency) channel

·      Each has advantages/disadvantages

·      TIF: high quality, high amount of data, not Internet friendly. For printing use only.

·      JPG: Stands for Joint Photographers Expert Group; in a LOSSY format, can reduce a file size by 10:1, level of compression is adjustable. Don’t re-compress files, will make it look bad.

·      GIF: stands for Graphic Interchange Format. Is best for graphics or images that have flat color or even tone, like a cartoon. Reduces image size by “indexing” color from 3 channels to 1. Terrible for printing.

·      For best quality TIF for printing or PNG of web use

·      For smallest file size use JPG

·      Maximum compatibility use TIF of JPG

·      TIF and JPG are best for images with pixels that blend in color, these are called “continuous pixels”

·      GIF is best for images with flat even tone, or “non-contiguous pixels”

·      Alias vs. Anti-Alias: Aliased has jagged edges, anti-aliased is blended together