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HP
PrecisionScan Pro
User’s Guide
94
Adjusting images of
pictures
Book Contents
Index
➮
➮
Set color channel for black and white bitmaps
When you want to save a black and white bitmap of a
picture that has been printed or photocopied on
colored paper, or want to create a special effect, you
can change the color channel used in the final scan.
Eliminating a color from the image
By changing the color channel setting in the
Black &
White Threshold
tool you can eliminate red, green or
blue from the image (see page
95
).
1
Scan a picture.
2
From the
Tools
menu, select
B & W Threshold
.
The
Black & White Threshold
tool appears.
3
From the
Output Type
menu, select
Black & White
Bitmap (raster)
.
The image changes to black and white.
4
Decrease the value for the black and white threshold
(see page
93
).
5
Select a color channel from the
Scan using channel
list
box in the
Black & White Threshold
tool:
■
To eliminate all the red in colored line art or from a
drawing printed on red or pink paper, choose the
Red
channel. The red components of each pixel in the
image will be mapped to white and green and blue
components of each pixel will be mapped to black.
■
To eliminate all the green in colored line art or from a
drawing printed on green paper, choose the
Green
channel. The green components of each pixel in the
image will be mapped to white and red and blue
components of each pixel will be mapped to black.
■
To eliminate all the blue in colored line art or from a
drawing printed on blue paper, choose the
Blue
channel. The blue components of each pixel in the
image will be mapped to white and red and green
components of each pixel will be mapped to black.
The
Auto
button in the
Black & White Threshold
tool
does not reset the color channel.
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