Graphic Design Notes

Graphic Design

Graphic File Formats

Understanding Format Choice and Image Compression

• Gif = Worst Quality for Printing Art Work
• Compression = Makes the work worse

File Formats

• All Computer documents or files are packaged in different formats
• The format is determined often by the origin of the file, such as a software program like photoshop or a device as a digital camera

Lossy vs Lossless

• Graphic image formats fall under 2 catagories of compression, Lossy and Lossless
• With Lossy, image data is “lost” or reduced for smaller file sizes and can cause poor image quality (pixelation)
• Lossless retains image data for higher quality, but for 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 and disadvantages

File Format: TIF

• Stands for Tagged Image Format
• Common format for desktop publishing, print, photo, and Graphic design

File format: JPG

• stands for Joint Photographers Expert Group
• Created for digital Photography and works best for photo content
• Has a Lossy format
• can reduced a image file size by 10 : 1
• level of compression is adjustable

File Format: GIF

• stands for Graphics Interchange Format
• Is best for graphics or images that have a 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 best for images with pixels that blend in color, these are called “Contigous Pixels”
• GIF is the best for images with flat even tone, or “non-contigous pixels”