User manual

22 • Sharpening an image (unsharp masking)
ColorQuartet 5.0 Pro
192
Setting USM manually and viewing USM feedback
Manual adjustment of USM should only be done if you are not satisfied with the results of the
automatic USM function
.
The Unsharp Masking window lets you adjust the USM settings manually and, if desired, save
them for repeated use. It also lets you interactively view the effect
of your USM settings so you
can evaluate them before doing the final scan.
To open the Unsharp Masking window, choose Custom... from the Unsharp Masking menu in
the top section of the Sc
an Setup window or choose Unsharp Masking from ColorQuartet’s
Color menu.
If you change anything in the Unsharp Masking window, the Unsharp Masking menu in the
Scan Setup window will automatically change to Custom....
The individual functions in the Unsharp Masking window are described below.
Strength
The Strength function is a “master control” that increases or decreases the overall level of
unsharp masking.
This is the first parameter you should adjust if you think the sharpness of an image needs to be
changed. If the desired result is not obtained, you may need to adjust other USM parameters.
Radius
Radius determines the number of surrounding pixels (from 1 to 5) that ColorQuartet takes into
account when deciding whether to sharpen any given pixel.
The higher the Radius, the greater the sharpening effect.
Contour
The Contour functions determine the intensity of the contrasting edges that appear around
objects that are sharpened.
The higher the value chosen, the clearer the contours will be.
Dark Contour affects the edges around pixels that are darker than their surroundings.
Light Contour affects the edges around pixels that are lighter than their surroundings.
Threshold
The Threshold functions tell ColorQuartet how much contrast there must be between adjacent
pixels before sharp contours are produced.