Understanding File Format

File formats

*All computer documents, or files are packaged in different formats

*The format is determined often by the files origin, such as a software program like Photoshop, or a device such as digital camera.

*Graphic files such as photo, video, or artwork can be reduced in file size by using image compression formats

Lossy vs Lossless

*Graphic image formats fall under 2 categories of compression, Lossy or Lossless

*With Lossy, image data is "lost" or reduced for smaller file sizes but can cause poor image quality. Can result in showing "compression artifacts"

*Lossless retains image data for higher quality, but larger file sizes

Graphic formats

*TIF,JPG, and 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 format has its own advantages, disadvantages

File Format: TIF

*Stands for Tagged Image Format

*Common format for desktop publishing, print, photo, and graphic design

*Is a LOSSLESS file format. It retains image data for maximum image quality

File Format: JPG

* Stands for Joint Photographers Expert Group

*Created for digital photography and works best for photo content 

*Is a LOSSY format

*Can reduce an image file size by 10:1 with out showing significant compression artifacts

*The level of compression is adjustable

File Format: GIF

*Stands for Graphics Interchange Format

*Is the best for graphic or images that have flat color or even tone, such as a cartoon

*Reduces image size by "indexing" color from 3 channels to 1

*Is adjustable by changing color bit levels from 1 to 8

*Contains no DPI (Dots Per Inch) data for printing. Not a proper format for print

Know your Pixels

*TIF and JPG are the best for images with pixels that blend in color, these are called "contagious pixels"

*Gif is the best for images with flat even tone, or "non-contagious pixels"