| Scanners
Key Components
Choosing the right scanner involves a number of different criteria,
none more important than bit depth, resolution, dynamic range, and
color. While the reason for buying a scanner and what you intend
to scan are key decisions to consider, these four components will
affect the quality of a scan regardless of how it is used in the
office.
Bit Depth
When a scanner reads an image, it breaks down what is read into
small dots, or pixels. Based on the quality of the machine, a scanner
can record varying amounts of information about each pixel. The
amount of information that the scanner can remember about each pixel
is commonly referred to as bit depth.
A scanner with
a bit depth of one can only distinguish whether a pixel is white
or black, with each increase in bit depth representing an ability
to record more details about an image's color or gray scale.
For black and white scans, a 12-bit scanner will usually provide
adequate reproduction of over four thousand shades of gray. Bit
depth for color scans can be broken down by how many bits the scanner
can process for each primary scanning color - blue, red, and green.
An eight bit
scanner can identify 256 colors for each pixel; a 24-bit scanner
can reproduce 16.7 million colors. For most business purposes, a
24-bit machine is sufficient.
There are also
scanners on the market at 30- and 36-bit depths, which is more color
than the human eye can distinguish. While most software systems
today cannot accurately process the billions of colors that come
with such high bit-depths, the extra information helps to clean
up images that may be affected by noise or other losses in the image
transfer. In turn, those seeking the highest quality of color reproduction
should look into 30- or 36-bit depths instead of 24.
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