By default, the printer driver transfers binary information to PostScript printers; however, you can choose to transfer image data using JPEG or ASCII85 encoding. (ASCII85 is a text-encoding method for binary data; it is more compact than ASCII encoding.) These options are not available for non-PostScript printers, including many inkjet printers.

Because JPEG-encoded files are smaller than binary files, they take less time to print; however, using JPEG encoding decreases image quality. Only PostScript Level 2 (or higher) printers support JPEG encoding; if you send a JPEG-encoded file to a PostScript Level 1 printer, you may get PostScript language errors.

Some print spooler programs, computer networks, and third-party printer drivers don’t support binary files or JPEG-encoded files. Also, some PostScript output devices accept binary and JPEG-encoded image data only through their AppleTalk and Ethernet ports, not their parallel or serial ports. In these situations, you can select the ASCII85 encoding method. However, ASCII85 files contain about twice as many characters and take twice as long to transfer as binary files.