Graphic File Formats Notes, Liam Conley, per 2

• All com. doc., or files are packaged in dif. formats
• the format is determined often by the files origin such as a software program like photoshop. or a digital cam.
• Graphic file such as a photo, video or artwork can be reduced in file size by using compressors

Lossy v lossles

• the 2 categorys
• w/ lossy data is “lost” or reduced for smaller file sizes but cause poor image qualt. can result in compresion artifacts
• lossles retains image data

Graph. formats

• Tif, Jpeg and Gif are the 3 most com. formats for activities such as printing, scanning and displaying over the internet
• Png is a common web format is a common web format, is high quality and can contain an alpha channel
• each format has its own dis/advantages

Tif

• tagged image format
• common format for desktop pub., print, photo, and graphic des.
• is lossless file. retains image data
• can result in larger file sizes not fit for display over internet, not browser compatible

JPG

• stands for joint photographers expert group
• created for digital photography and works best for it
• is lossly
• can reuce 10:1 w/out showing compression artifacts
• the level of compression is adjustible

GIF

• graphics interchange format
• is best for flat colors such as cartoons
• reduces image size by “indexing” color from 3 channels to 1
• is  adjustible by changing color bit levels from 1 to 8
• contains no DPI data for printing

Which format should I use for ____?

Best qual. Tif Png

Smallest file size JPG

Max compatibility TIF JPG

worst choice for photos GIF

worst choice for line art JPG

Know your pixels

• Tif and JPG are best for images w/ pixels that blend in color called contiguous pixels
• Gifs are best for flat images or non contiguous pixels

alias v anti-aliase: jagged v softened