perceive definition, particularly with respect to distant or other-
wise vague objects. A highly defined edge with sharp transitions
between light and dark tells us where an object begins and ends.
But so what if it’s a contrast trick? After all, photography itself is a
trick that simulates reality, specifically geared to human eyes and
brains. If Photoshop’s sharpening augments that trick, more power
to it. I just want you to know what you’re doing. After all, the ma-
gician who truly understands his bag of tricks is better equipped
to perform magic.Sharpening an Image
Of the five filters that reside in the Filters→Sharpen submenu, only
two, the ancient Unsharp Mask and the more recent Smart Sharpen,
let you control the amount of sharpening you apply to an image. As
a result, they do everything the other three filters do—which isn’t
much, frankly—plus a whole lot more.
Unsharp Mask derives its name from an old and largely abandoned
traditional darkroom technique in which a photographic negative
is sandwiched with a blurred, low-contrast positive of itself and
printed to photographic paper. Ironically, this blurred positive (the
“unsharp” mask) accentuated the edges in the original, resulting in
the perception of sharpness.To see how Unsharp Mask’s arcane origins translate to
the way Photoshop’s sophisticated sharpening functions
work, read the upcoming sidebar “Using Blur to Sharpen”
on page 224.These days, Unsharp Mask takes a back seat to Smart
Sharpen, which incorporates the best of Unsharp
Mask’s capabilities and adds a few of its own. This
is why we’ll focus exclusively on Smart Sharpen in
the following tale of rodent romance.- Open an image. Go to the Lesson
07 folder inside Lesson Files-PsCS5
1on1 and find Rodents in love.psd (see
Figure 7-3). Cute as this squirrely story is, the
image suffers from a tiny amount of lens blur,
meaning that it’s a bit off from its ideal focus.
Figure 7-3.
220 Lesson 7: Sharpening and Smart Objects