Graphic Considerations

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You've read it all before, but here are the basics. Different file types are available for different end uses of the file. When it comes to working on the Web, there are four basic file types that work efficiently in one instance or another:

GIF, JPEG, PNG, and SWF. Each has a specific use, sort of like a doctor specializing in feet, lungs, or eyes.

GIF (pronounced "Jiff" or "Giff," Graphic Interchange Format) is good for large blocks of solid color. These blocks shouldn't have gradients or soft variations in color or tone. If they do, banding occurs, due to the number of colors involved in the eight-bit color file. Think of a block of red next to a block of yellow. If you create a 25-step gradient between them, you will get various shades of orange in a smooth, blended gradient. But if you only have two steps the jump between red and yellow is pretty severe, with only two shades of orange. This creates steps between the colors called banding. You can decide to have a few colors or as many as 256 colors depending on the type of artwork or project you're working on.

JPEG or JPG (pronounced "Jay Peg," Joint Photographic Experts Group) is best suited for continuous tone images. This file compression type is faithful to smooth gradients, but it leaves unsightly artifacts or blotches in large blocks of solid color — especially noticeable in reds. This type of compression results from a user-defined degradation of the image. It is the most efficient method of compression for continuous tone images, but it does so at the expense of a lot of data that is discarded.

PNG (pronounced "Ping," Portable Network Graphics) is the cream of the bitmap crop, giving up to 32-bit images and alpha channel support for transparency. But it's not supported on all browsers. Microsoft Internet Explorer 5.0 supports PNG, as does Netscape Navigator 6.0, but it has a small audience right now.

SWF (pronounced "Swiff," ShockWave Flash,) is a format for saving vector art especially for placement in Flash pages. Exporting a FreeHand file in SWF format maintains the sharpness and smoothness of vector art at any size, allowing the artwork to be magnified or reduced without image degradation — and it happens on the fly. Animations are an excellent use of SWF file export. Because you're working with vector files in the first place, SWF compression is extremely efficient, and files are quite small.

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