dimensions of the final image are typically known. For example, when a page layout
reserves a 4" x 6" space, a 4" x 6" scanned image is produced to fit.
The resolution of the scan, either input or output, will determine the amount of
data that is present in the scan, e.g. the amount of data in the 4" x 6" area. If the out-
put resolution was set at 100 pixels or dots per inch, the resulting scan file would be (4 x
100) x (6 x 100) = 240,000 pixels or dots. If the output resolution was set at 200 pixels
or dots per inch, the resulting file would be (4 x 200) x (6 x 200) = 960,000 pixels or
dots. Both images would still, however, occupy the same 4" x 6" space when used at
their respective resolution settings.
So what is the basis for selecting resolution? The higher the resolution, the better
the scan detail, the longer it takes to produce the scan, and the larger the resulting file
size. Typically, the resolution of the scan is selected to best suit its intended use, in par-
ticular the device it will be output on. To match any output device that has 300 dots
per inch, the final resolution might be selected to be 300 pixels per inch.
This simple rule does not necessarily apply for all applications. For example,
when your intended output is for offset or printed reproduction, the scan resolution
should be between one and two times the required printing screen resolution.
Final Resolution
Macintosh: Final resolution is measured in either pixels/inch (ppi), pixels/mm or
pixels/cm. As you learned in the previous chapter, the number of pixels in the final scan
will equal the value of this parameter multiplied by the width and the height values.
The resulting
S
CAN
R
ESOLUTION
and
P
ITCH
setting of using 72, 144 and 288 ppi
F
INAL
R
ESOLUTION
settings are shown in Figure 11.18a. The
W
IDTH
and
H
EIGHT
remain constant. Note, however, that the scan
P
ITCH
, the
S
CAN
R
ESOLUTION
and the
F
ILE
S
IZE
vary accordingly.
Page 104
Software Reference for Scanners
Cropping and Sizing Images
Chapter 11
Summary of Contents for Scanners
Page 1: ...Software Reference for Scanners ...
Page 14: ...Page XIV Software Reference for Scanners Table of Contents ...
Page 36: ...Page 22 Software Reference for Scanners Software Installation IBM PC or Compatible Chapter 3 ...
Page 126: ...Page 112 Software Reference for Scanners Cropping and Sizing Images Chapter 11 ...
Page 132: ...Page 118 Software Reference for Scanners Film Type and Orientation Chapter 12 ...
Page 146: ...Page 132 Software Reference for Scanners Focusing with Coolscan Chapter 14 ...
Page 170: ...Page 156 Software Reference for Scanners The Gamma Curve Editor Dialog Chapter 16 ...
Page 194: ...Page 180 Software Reference for Scanners Troubleshooting Windows ...