Plustek Opticpro A320E Flatbed Scanner - Manual (Page 214)

MacAction Help 42
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Gamma
Image Gamma is used to adjust the colors in the image that will be scanned into
the computer. Gamma values are primarily a measure of the brightness of a color.
The larger the gamma value, the brighter the color becomes.
Do one of the following:
· Slide the thumb of the scroll bar to the right or left.
· Click on the scroll bar.
The current value is shown to right of the scroll bar.
This feature is not available when Black & White is selected as Scan Mode .
Threshold
Threshold sets the color level for converting an image to line art, which can adjust
the quality of line art image or eliminate unwanted dots in the documents to
improve OCR accuracy. This setting is available only when
Black & White is
selected as Scan Mode.
You may adjust the Threshold value either way:
· Slide the thumb of the scroll bar to the right or left to decrease or increase
the Threshold value.
· Click on the scroll bar.
The current value is shown to right of the scroll bar.
Color Dropout
Color Dropout allows you to remove a color channel (Red, Green or Blue) while
scanning. This feature is available only when
Black & White or Grayscale is
selected as Scan Mode.
For example, if your original document contains blue texts or a blue stamp (e.g., a
bill or invoice) and you want to discard it from your image, you may select
Blue
Channel from the drop-down list box