|JPG, GIF, PDF, EPS? Choosing the Proper Graphic File Formats for Web Pages and Print|
Using the proper graphic file format and resolution for the job can mean the difference between a professional-looking document and one that looks blurry or is missing graphics. Graphic file formats for the Internet and offset printing are totally different animals. Do not interchange them!
Graphics File Formats for the Internet
Scan your photos using RGB colors to the JPG file format. JPG file sizes are very small and compatible with nearly every graphical browser. This format is best suited for photographs and any image that contains a complex mixture of colors.
The GIF format is best suited for images with a limited number of distinct colors and graphics that have sharp, distinct edges (most logos, menus and buttons). A special GIF89a file format gives you the option to make the background transparent so you don’t get a white rectangle behind the graphic.
Graphics File Formats for Offset Printing
Offset printed graphics can be one of two types: Vector-based or high-resolution raster. Raster images (which are color or grayscale digital photos and scans) must be at least 300 PPI (pixels per inch) and in the TIF (Tagged Image File) or EPS (Encapsulated PostScript) file format. Your scans of black and white line art (images that do not contain any shades of gray) must be at least 1200 PPI. Be careful not to enlarge your raster graphics, because the pixels will also enlarge and become more noticeable.
Vector-based graphics are made of mathematically defined lines and curves. Because they are not made of pixels, these unique files can be scaled to any size without losing their crisp, smooth edges. Use professional drawing programs such as Adobe Illustrator, Macromedia Freehand, or Corel Draw to create these types of graphics for printing, saving them in the EPS format.
Color Ink Systems for Printing