To compare the sharpened and original versions, click the portion
of your photograph that appears in the Unsharp Mask window, and
hold down the left mouse button.
6) Reduce the opacity of the composite layer to reduce the amount
of sharpening.
Evaluate
Compare the unsharpened and sharpened versions by selecting and
deselecting the eye icon on the layer being sharpened.
Enlarge your photograph to 100%, and review the most important
part of the photograph.
Evaluate the sharpening by checking the following.
• Detail should be evident, but not blaringly so.
• There shouldn't be any halos along the edges in the photograph.
• Look for any increase of noise in areas with even tones or
colors.
Increase the threshold to reduce any noise.
Then, reduce the amount, if needed.
As mentioned, you can change the sharpening by varying the opacity
of the sharpening layer.
This may be convenient if you're printing a photograph at various
sizes, each of which may require a different level of sharpening.
Color Shift
If sharpening creates a change in color, try sharpening only
the luminosity information from your photograph, and not the color
information.
Create a separate luminosity layer from the composite layer,
and use the luminosity layer for sharpening.
