CHAPTER 15 THE IMPORTANCE OF LEVELS AND CURVES 225■ Black slider triangle.Move this control to the right to force grays to black.
All tones to the left of the slider will become black.
■ Gray slider triangle.Use this slider to re-adjust the average gray value
(50% black). If you slide this triangle to the right, the image will become
darker because lighter tones will be forced to 50% black. Shift the gray slider
to the left to force darker tones to 50% black. This will lighten the image.
Most images suffer from lack of contrast, which involves the white and black
triangle sliders, not the gray slider. For images that do not need much adjust-
ment, use the gray slider to give the image a little more punch. For example,
slide the gray triangle to the right to force lighter values to middle gray,
which will make the image a little darker.
■ White slider triangle.Move this control to the left to force grays to white.
All tones to the right of this slider will be turned white in the image.The Output Levels Section
The Levels dialog box includes two sections: Input Levels and Output Levels. This
chapter focuses only on the Input Levels section in the Levels dialog box. The Output
Levels section at the bottom of the dialog box is mainly used for offset
(magazine/book/newspaper) printing. Output Levels includes a gradient through
which you can force tones to a specific brightness.FIGURE 15.9
Move the sliders
under the his-
togram to force
tones to pure
black and pure
white.