HP 815MFP - Manual (Page 83)

hp designjet 815mfp & scanner 4200 77
background clean value. As with black enhance, background clean
should be used with caution, as it can also affect some of the other
light colors.
Both black enhance and background clean function as ‘cutoff’
values in which pixels under or over a certain value are affected by
the setting. You define cutting points on a scale of low to high
lightness measured in values from 0 to 255. The default value of
both options is zero (no effect).
Example:
You have copied an original and want to improve it by making the
text blacker and the background whiter:
• Adjust the black enhance value upwards from its default of
zero (to 25, for example) and thus make pixels with low
lightness values go to black.
• Adjust the background clean value upwards from its default of
zero (to 25, for example) and thus make the pixels at high
lightness levels go to white.
You can give your copy sharper lines with the Sharpen option. The
Sharpen feature identifies edges in the image and intensifies them.
sharpen/blur
The Blur feature blends colors and thus removes unwanted ‘noise’
during image capture. Many images are created with dithering,
which is used for representing different colors in the original, and
this dithering often creates unnecessary ‘noise’ in the image.
Blurring smoothes out unwanted transitions between colors. With
Black and White copying the Blur feature smoothes out gray dither
by removing unwanted sharp transitions between excessive shades
of gray.
Don’t think of blurring as the opposite of sharpening. Sharpening
works on the image’s edges only while blurring looks at whole color
or graytone areas and smoothes them out.
tip
Using Sharpen together with the Blur feature can often enhance
image quality by first blurring away noise in the image and then
sharpening the result.