Graphics Programs Reference
In-Depth Information
8.
Hold down Opt and click to zoom out. Notice how holding down Opt
temporarily toggles the Zoom Out button on the options bar.
9.
Click the Fit Screen button on the options bar (or double-click the
Hand tool). You can see the whole image with its aspect ratio pre-
served. Click Fill Screen and it might zoom in or out depending
on your monitor's aspect ratio so that pixels fill the entire screen.
Double-clicking the Zoom tool displays the actual pixels at 100%
magnification.
Fit Screen respects
the document's
aspect ratio, whereas
Fill Screen respects
your monitor's
aspect ratio.
10.
Click the Print Size button. The picture zooms to approximate the
document's resolution (see “Setting Document Size and Resolution”
later in this chapter). Double-click the Zoom tool. The document zooms
to 100% magnification. This is equivalent to clicking the Actual Pixels
button on the options bar. You will want to view photos at 100% when
sharpening them.
For more about
sharpening photos,
see Chapter 12,
“developing photos.”
Understanding Color
Color is a very powerful visual element, and numerous topics have been written
on the subject. In the following sections I'll discuss the fundamentals: how color
is represented by primary colors, why primaries are stored in channels, the dif-
ferences between color modes, and how to pick color in Photoshop.
Certification
Objective
See Chapter 15,
“Working with
Color” for more
information about
managing, correct-
ing, adjusting, and
proofing color.
Using Primary Colors
Although the human eye can distinguish between about 10 million different
colors, we can agree on names for less than a dozen. Figure 3.6 lists additive pri-
maries in white, subtractive primaries in black, and tertiary colors in gray.
Just as any point can be represented in 3D space as a set of coordinates taken
along the X, Y, and Z primary directions, any color can be represented as a combi-
nation of three primary colors. However, color is complicated because the nature
of light changes depending on whether it shines directly in your eyes or reflects
off a surface before entering your eyes.
Light emitted from a computer monitor, or light captured by a digital camera
or scanner sensor, is additive. Red, green, and blue (RGB) are the primary colors
of additive light. Cyan, magenta, and yellow are secondary colors in the RGB
system. Figure 3.7 shows that if you add equal intensities of red, green, and blue
light together, you get pure white. All the colors of the rainbow are in white light.
