Operation Manual

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The Tool Chest — Unsharp Mask
Creating Unsharp Masks
Step 1—Select a Color
Select a color from the color menu. Masks apply only to
edges where the selected color predominates. To create a
mask that applies to all colors, select All.
Intensity The amount the contrast of edges will be increased.
Halo
Width
The size of the area that will be affected. The greater
the halo width, the wider edges will appear. Too large a
value for halo width will produce a “halo” along edges
in the image.
Threshold
The limit at which sharpening will be applied. If the
threshold is zero, sharpening will apply to all pixels in the
image. Increasing the threshold increases the amount of
contrast that must be present between pixels before the
mask will be applied, with the result that only more dis-
tinctly contrasting edges will be affected.
Step 3—Check the Results
To compare the effects of the Unsharp Mask with the un-
modifi ed image, click the “Apply” button at the top left
corner of the “Unsharp Mask” palette to turn the effects of
Unsharp Mask on or off.
Step 4—Create Additional Masks
Repeat steps 1–3 to create additional masks for different
colors. New masks will be added to the end of the Unsharp
Mask list. Masks apply in the order listed. To change the
order, select a mask in the Unsharp Mask list and click
to move it up in the list or
to move it down. To delete a
mask, select it and click the
button.
Step 2—Set Intensity, Halo Width, and Threshold
Use the sliders or enter values directly in the text boxes to
their right.