Adobe Photoshop CS5 One-on-One

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ADJuSTIng COLOR AnD

LuMInAnCE

Figure 6-1.

Figure 6-2.

DeeP InSIDe the most primitive recesses of

our minds—where thoughts such as “must eat to
live” reside—we possess an implicit un-
derstanding of luminosity. Sun-
light illuminates all things on
this planet. And those things re-
flect highlights and cast shadows.
These highlights and shadows
permit our eyes to distinguish form,
texture, and detail. We need variations
in luminosity to see.

By comparison, color is a subjective abstrac-
tion. Can you elegantly describe orange or pur-
ple, words that you’ve bandied about since you
were a tot? And who’s to say what you call orange
I might not call scarlet, amber, or even red? In
day-to-day life, our tenuous understanding of
color is generally sufficient. After all, it seems
like color is mostly window dressing. We
don’t use it to identify; we use it to clarify.

However, as illustrated in Figure 6-1, you rec-
ognize a strawberry by its luminosity; you know
whether it’s ripe by its color. If Figure 6-2 is any in-
dication, without variations in luminosity, you’d
have a hard time identifying anything in the first
place. But knowing which fruit is ripe, rotten, or
possibly poisonous probably requires color distinc-
tion. Fortunately, Photoshop has excellent tools for
controlling both luminosity and color in your images,
as we’ll see in this lesson.

A strawberry is a

strawberry

Red makes it ripe

By itself, color conveys

little more than a vague imprint

of an object, yet one that imparts

critical information