Adobe 29180155 User Guide - Page 134

ADOBE PHOTOSHOP ELEMENTS 4.0 129 User Guide Grayscale images have a single channel option: Gray. 5 To view the following statistical information about a range of values, drag and hold in the histogram to highlight the range, or to view information about a specific area on the histogram, place the pointer over the area: Mean Represents the average intensity value. Standard Deviation (Std Dev) Represents how widely intensity values vary. Median Shows the middle value in the range of intensity values. Pixels Represents the total number of pixels used to calculate the histogram. Level Displays the intensity level of the area underneath the pointer. Count Shows the total number of pixels at the intensity level underneath the pointer. Percentile Displays the percentage of pixels at and below the level underneath the pointer. This value is expressed as a percentage of all the pixels in the image, from 0% at the far left to 100% at the far right. Cache Level Shows the setting for the image cache. If Use Cache For Histograms is selected in the Preferences dialog box, Photoshop Elements displays histograms more quickly but less accurately. To display more accurate histograms, deselect this option. Adjusting shadows and light About Levels adjustments The Levels dialog box is a powerful tonal and color-adjustment tool. You can make levels adjustments on the entire image or a selected portion. A B C D Levels dialog box A. Channels to adjust color B. Shadow values C. Highlights value D. Middle tones You can do any of the following with the Levels dialog box: • Set the shadow and highlight values to make sure that your image uses the full tonal range. • Adjust the brightness of the image's middle tones without affecting the shadow and highlight values. • Fix a color cast by making grays neutral. You can also enhance an image by adding a slight color cast, for example, by adding a warming effect on a sunset. • Target shadow and highlight RGB values if you are preparing images for commercial printing.