Unlike the adjustment layers you saw in Lesson 6,
filter application is a destructive edit that alters pix-
els in an unchangeable way. One way to protect your
image from this irreversible damage is to wrap it up
in a smart object, a Photoshop feature that keeps the
original image safe inside a virtual protective container.
You can put an image or a vector illustration inside
this vessel, and no matter how much you scale, ro-
tate, warp, or filter it, Photoshop always references
the original art and re-renders it to achieve the best
possible transformation. Admittedly, smart objects
suffer the occasional limitations. If you want to paint
or edit a smart object, you have to open it in a sepa-
rate window. Even so, they’re astonishingly powerful
and a welcome addition to the application.
The Subterfuge of Sharpness
When an image is formed by the camera lens, the
image’s focus is defined. The moment you press the
shutter, you accept that focus and store it as a perma-
nent attribute of the photograph. If the photograph
is slightly out of focus, it stays out of focus. No post-
processing solution can build more clearly defined
edges than what the camera actually captured. Al-
though Photoshop can’t reach back into your camera
and modify the lens element for a better shot, it can
compare neighboring pixels and enhance already
existing edges. Your eyes think they see a differently
focused image, but really they’re seeing an exagger-
ated version of the focus that was already there.
Consider the photos in Figure 7-2. The first comes from
an image that was shot to film and then scanned. This
macro shot includes a generous depth of field, with
the focus varying from dead-on in the eyes to soft as
the creature’s scales bulge toward us or recede away.
The second and third images show variations imposed
by Photoshop. (For the sake of demonstration, I ap-
plied the sharpening over the softening.) Softening
blurs the pixels together; sharpening exaggerates the
edges. Softening bears a strong resemblance to what
happens when an image is out of focus. Sharpening
is a contrast trick that exploits the way our brains
Real camera-defined focusPhotoshop-imposed softening (Filter Blur Lens Blur)Photoshop-imposed sharpening (Filter Sharpen Smart Sharpen)Original photograph istockphoto.com/geckophotoFigure 7-2.The Subterfuge of Sharpness 219