You think you have found the almost-perfect image on a Web site but it's not quite the right size. You make it bigger and suddenly it looks awful. You send it to a friend but they can't open it. You've hit several of the possible snags encountered when using graphics in desktop publishing. There's more to using graphics than finding a picture that you like.
Understand Graphics Formats
There are two basic formats: bitmap or pixel-based and vector. Web or screen display uses bitmap images. Print projects can use either format. Photographs are bitmap or pixel-based images. Clip art can come in either format. Bitmap images do not resize easily or cleanly and are best used at the size at which they were created. Vector images resize easily and with less distortion. They can be used at very large or very small sizes without loss of quality most of the time.
Choose Graphics File Formats
Most graphics file formats are either bitmap or vector. GIF, PCX, JPG, and TIFF are bitmap examples. Vector file formats include EPS, CGM, PICT, and WMF. For the Web, low-resolution GIF and JPG are the most common formats. For commercial desktop publishing TIF (bitmap) and EPS (vector) are the preferred formats. Other formats, while suitable for desktop printing, may not give good results or be incompatible with the software or resolution requirements of commercial printing.
Choose Graphics Software
Most print publishing needs an illustration program and an image editor for graphics. Some programs may incorporate features of both, but for most professional work you'll need each one. Each type of graphics program works primarily with either bitmap or vector images. Adobe Photoshop is an example of an image editor that works with GIF, JPG, TIF, and other bitmap graphics file formats. CorelDRAW is an example of an illustration program used primarily for EPS and other vector file formats.
Use the Right Color for Your Graphics
The two most common color models are RGB and CMYK. In RGB, the color of the Web, images are displayed using combinations of Red, Green, and Blue. It's OK (and often preferrable) to work with images in RGB format in your software. But when it comes time to have those graphics commercially printed they need to be converted to CMYK before placing the images in your desktop publishing document. Your graphics software can easily handle this task.
Know Your Copyrights When Using Clip Art and Photos
Just because a piece of clip art or a photo is on the Web does not mean you can use it. Just because you purchased a graphics collection does not mean you can do anything you want with those images. What you can and can't do with a photo or illustration depends on what the copyright holder and your license agreement allows. The only way to know for sure is to read, research, or ask.
Choose the Right Graphics Image
A graphics image in the right format that you have permission to use in the way you intend is just part of the process of using graphics in desktop publishing. You also need to choose and use appropriate images.