User`s manual

1-9Basic Concepts
Resolution determines the level of detail recorded by the scanner,
and is measured in dots per inch (dpi). The greater the dpi
number, the higher the resolution and the resulting file size.
Image quality improves with higher resolution, but only up to a
certain point, after which increasing resolution simply makes file
sizes unmanageable without yielding any visible improvement to
the image. For most applications, scans of up to 300 dpi are
adequate.
When dealing with resolution, it's important to distinguish
between optical, or true, resolution, and interpolated resolution,
which is resolution enhanced through software.
• Optical resolution is the key factor in determining the
sharpness and clarity of an image.
• Interpolated resolution, or resolution enhanced through
software, is useful for certain tasks, such as scanning line art
or enlarging small originals.
Choosing the best resolution setting
Scanning at a higher resolution requires more time, memory, and
disk space. When choosing a resolution setting, consider the type
of image you're scanning and the printing method. Printed images
have their own resolution, as measured in lines per inch (lpi),
which is distinct from the resolution of electronic images (as
measured in dpi).
An easy way to determine the best resolution for your intended
output is to find out the lines per inch (lpi) capability of your
output device and multiply it by 1.5 to 2.0.
For instance, to tailor your scanned image to a typical magazine
printing press that prints at 133 lines per inch, multiply 133 x 1.5
or 2.0, which gives 199.5 or 266. In this case, the optimal
resolution setting for your image would then be 200 dpi to 266
dpi (depending on how high the output quality will be). Lpi
varies, depending on the quality of the printing job. A newspaper
uses approximately 85 lpi, magazines from 133 to 150 lpi, and
fine art books may go as high as 200 to 300 lpi.
If you're outputting images to a monitor (such as doing multime-
dia work), you need not scan images higher than 72 dpi, as
monitors are capable of only showing images up to 72 dpi. A
higher-resolution image will not be any clearer on the monitor
and will simply create larger files.
Resolution