User's Manual

279
ADOBE PHOTOSHOP CS2
User Guide
To preview histogram adjustments
You can preview the effect to the histogram of any color and tonal adjustments.
❖ Select the Preview option in the dialog boxes of any color or tonal adjustment command.
The Histogram palette displays a preview of how the adjustment affects the histogram.
A
B
C D E
Preview of histogram adjustment in the Histogram palette
A. Original histogram B. Adjusted histogram C. Shadows D. Midtones E. Highlights
To refresh the histogram display
When a histogram is read from a cache instead of the document’s current state, the Cached Data Warning icon
appears in the Histogram palette. Histograms based on the image cache are displayed faster and are based on a repre-
sentative sampling of pixels in the image. You can set the cache level (from 2 to 8) in the Memory And Image Cache
preference.
❖ To refresh the histogram so that it displays all of the pixels of the original image in its current state, do one of the
following:
• Double-click anywhere in the histogram.
• Click the Cached Data Warning icon .
• Click the Uncached Refresh button .
• Choose Uncached Refresh from the Histogram palette menu.
For information about cache level, see “To view histogram statistics” on page 278.
Viewing the color values of pixels
Youcan usethe Info paletteand theColor palettetosee thecolor valueofpixelsasyou make colorcorrections.This
feedback is useful while you make color adjustments. For instance, referring to the color values can help when
neutralizing a color cast or can alert you that a color is saturated.
When you work with a color adjustment dialog box, the Info palette displays two sets of color values for the pixels
un
der the pointer. The value in the left column is the original color value. The value in the right column is the color
value after the adjustment is made.