724
ADOBE PHOTOSHOP CS2
User Guide
Choosing a print encoding method
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.
To change the encoding method
1
Choose File > Print With Preview.
2
Select More Options (it is already selected if Fewer Options is displayed), and choose Output from the pop-up
menu.
3
Select an option from the Encoding menu.
Creating color traps
A
trap
is an overlap that prevents tiny gaps in the printed image caused by a slight misregistration on press. Contact
your service provider before you do any trapping. In most cases, your print shop determines whether trapping is
needed. If so, the print shop staff will tell you what values to enter in the Trap dialog box.
A.
B.
A
B
Trapping to correct misalignment
Misregistration with no trap
Misregistration with trap