Scaling; Dynamic Range - Microtek ScanMaker IIG User Manual

Scaling

Scaling is the process of creating larger or smaller images in your
scanning software so that you need not resize the images later
when they are delivered to your image-editing program.
In the scanning software, scaling has an inverse relation to
resolution: The lower the resolution, the larger the image can be
scaled. At the highest resolution, images can only be scaled
smaller.
To illustrate the use of scaling, assume you scanned a 2" x 2" image at
300 dpi. To double image size to 4" x 4" without loss of detail,
increase scaling to 200% and maintain resolution at 300 dpi.
This is the same as scanning the image at 600 dpi at 100% scaling
— and then using your image-editing software to enlarge the
output. In the example above, image size was doubled through
scaling alone without having to use the image-editing software.

Dynamic range

Another important factor in obtaining quality scanned images is
the dynamic range of a scanner.
Dynamic range is the ability of the scanner to register a wide
range of tonal values — something from near white to near black.
A scanner with a good dynamic range is able to map input shades
correctly to the output shades, so you will be able to see more
detail in an image.
A scanner with poor dynamic range, on the other hand, will not be
able to detect as wide a range of tonal values. In this case, the
scanner will fill in the shadow areas or lose all detail in the
highlight in an attempt to map the colors correctly. What emerges
will be an image with less detail.
Microtek scanners have a dynamic range capable of registering a
wide palette of tones and translate these accordingly into photo-
realistic color. For instance, the ScanMaker III, Microtek's 36-bit
scanner, has a dynamic range of 3.4. (For comparison purposes,
anything above 2.0 is good, and anything above 3.0 is impressive.)
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