››PHOT OSHOP PROVIN G GROUND› ›kelbyone.com061we described above. The important thing is the concept,
because understanding those concepts sets you up to have
great control over sharpening tools.
APPLYING THIS TO THE SHARPENING TOOLS
Okay, here’s where we start applying this to the controls
you see in Photoshop. Generally, strength (or Amount)
values increase the multiplier values you see in the kernel.
That is, instead of –1, you might see –1.5, and 5 might be
replaced with 6. The bigger the difference between the
numbers, the more contrast in the result. The slider you
fiddle with adjusts all of the numbers in the kernel at once
so there’s no overall change in image brightness or color,
only contrast along edges.
Tip: You can try some of this yourself using Photoshop’s
Custom Filter. It’s under Filter>Other>Custom. Beware!
It only takes integer values; you can’t include decimals
as you can with the Radius and Amount sliders using
Smart Sharpen.
The Radius slider is a little different. What’s changing
there is how many pixels are included in the calculation.
So the size of the kernel actually gets bigger. This lets you
consider even bigger boundary widths and create broader
changes. Right away, it should make sense that larger
Radius values contribute to smoother sharpening, but you
risk generating halos; smaller Radius values can help bring
out fine details. And if you’re really thinking ahead, you’ll
see that multiple sharpening passes with small Radius and
Amount values will have a different effect than trying to
sharpen all at once with stronger values. [Note: For an in-
depth look at using the sharpening tools available in Adobe
Camera Raw and Photoshop, check out Martin Evening’s
feature article starting on page 62 .—ED] n
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