54

How to Scan

For details on using EPSON TWAIN HS or EPSON TWAIN HS Network, see 
page 58 and your electronic 

EPSON GT-30000 Reference Guide

. You can also install 

the ISIS driver and use it as your source. (See the 

ISIS User’s Guide

 on your 

GT-30000 Scanning Tools CD-ROM for details.)

Selecting Resolution

Resolution refers to how many dots per inch (dpi) or dots per centimeter (dpcm) your 
image contains. The best resolution for a scanned image depends on the type of image 
you’re scanning and your final output device. 

As a rule of thumb for most images except line art, use a scanning resolution that is 
approximately one third of your output resolution. For example, use a scanning 
resolution up to 100 dpi with a 300 dpi laser printer, and up to 200 dpi with a 
600 dpi laser printer. For 1440 dpi ink jet printers, such as the EPSON Stylus

®

Color 

series, use a scanning resolution of up to 300 dpi. Try a scanning resolution of 240 
dpi for 720 dpi printing.

Keep the following in mind when you choose a resolution:

■

The higher the resolution you select, the larger the resulting image file will be. For 
example, an 8.5 

×

11-inch original scanned at 300 dpi can produce a 24MB file. 

The same original scanned at 72 dpi creates a 1.3MB file. Large files take longer to 
process and print, so consider the practical limitations of your computer system 
and hard disk drive when selecting a resolution. To keep your file size 
manageable, select the lowest possible resolution that gives acceptable quality. (If 
your final output is for on-screen viewing, you can scan at 72 dpi and reduce your 
file size.)

■

If you need to scan at a higher resolution, you can reduce the size of the resulting 
image file by scanning only part of the image. For information about selecting 
part of an image, see “Making and Modifying Marquees” in your electronic 

EPSON GT-30000 Reference Guide

.