Deciding on a scanning resolution
Digital images are composed of square pixels, and pixel size is a
major factor affecting image quality. The resolution of an image is
expressed as the number of pixels per (linear) inch, abbreviated ppi,
or pixels per centimeter. Smaller pixels result in higher image resolu-
tion, which generally indicates better image quality. With scanned
images, the resolution is also a measure of how much information has
been captured from the original artwork.
At relatively low resolution, such as 75 ppi, lines, edges, and charac-
ter shapes in an image can appear jagged (see About digital images
and resolution on page 32.637). Scanning at higher resolution pro-
duces smoother images, which also require more memory and disk
space.
Use the following questions to help you decide what resolution is
appropriate when you scan images.
B
A
C
Scanning options
Plug-in acquire modules for
scanners offer various options.
Some standard scanning
options are described here.
Scan Mode or Color Mode.
Choose color, black and white,
or grayscale. These options
correspond to the RGB Color,
Grayscale, and Black & White
image modes in Canvas.
Resolution. Specify the scan
resolution in pixels (or dots)
per inch. Scanning at higher
resolution captures more
image information and results
in higher memory and disk
storage requirements.
Scaling. Enter a scaling per-
centage to reduce or enlarge
the image.
A
Use the preview area to
check the image and make sure
the area you want to scan is po-
sitioned correctly.
B
Many scanners let you drag
the corner of a scan rectangle to
select the area that will be
scanned. The selected area de-
termines the size of the image
object in Canvas.
C Most scanners offer bright-
ness or exposure controls. Refer
to the scanner documentation
for more information on adjust-
ing exposure settings.