Adobe photoshop cs2 Manual De Usuario
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ADOBE PHOTOSHOP CS2
User Guide
See also
Making quick overall adjustments to images
To use the Brightness/Contrast command
The Brightness/Contrast command lets you make simple adjustments to the tonal range of an image. Unlike Curves
and Levels, which apply proportionate (nonlinear) adjustments to the pixels in an image, Brightness Contrast makes
the same amount of adjustment to every pixel (a linear adjustment). The Brightness/Contrast command is not
recommended for high-end output because it can result in a loss of image detail.
and Levels, which apply proportionate (nonlinear) adjustments to the pixels in an image, Brightness Contrast makes
the same amount of adjustment to every pixel (a linear adjustment). The Brightness/Contrast command is not
recommended for high-end output because it can result in a loss of image detail.
1
Do one of the following:
•
Choose Image > Adjustments > Brightness/Contrast.
•
Choose Layer > New Adjustment Layer > Brightness/Contrast. Click OK in the New Layer dialog box.
2
Drag the sliders to adjust the brightness and contrast.
Dragging to the left decreases the level, and dragging to the right increases it. The number at the right of each slider
reflects the brightness or contrast value. Values can range from -100 to +100.
reflects the brightness or contrast value. Values can range from -100 to +100.
The Auto Levels command
The Auto Levels command automatically adjusts the black point and white point in an image. This clips a portion of
the shadows and highlights in each channel and maps the lightest and darkest pixels in each color channel to pure
white (level 255) and pure black (level 0). The intermediate pixel values are redistributed proportionately. As a result,
using Auto Levels increases the contrast in an image because the pixel values are expanded. Because Auto Levels
adjusts each color channel individually, it may remove color or introduce color casts.
the shadows and highlights in each channel and maps the lightest and darkest pixels in each color channel to pure
white (level 255) and pure black (level 0). The intermediate pixel values are redistributed proportionately. As a result,
using Auto Levels increases the contrast in an image because the pixel values are expanded. Because Auto Levels
adjusts each color channel individually, it may remove color or introduce color casts.
Auto Levels gives good results in certain images with an average distribution of pixel values that need a simple
increase in contrast.
increase in contrast.
Note: By default, Auto Levels clips the white and black pixels by 0.1%—that is, it ignores the first 0.1% of either extreme
when identifying the lightest and darkest pixels in the image. The default settings for Auto Levels can be changed in the
Auto Color Correction Options dialog box.
when identifying the lightest and darkest pixels in the image. The default settings for Auto Levels can be changed in the
Auto Color Correction Options dialog box.
See also
To use the Auto Levels command
1
Do one of the following:
•
Choose Image > Adjustments > Auto Levels. The application of Auto Levels is automatic with this option. You
cannot adjust any of the options in the following steps.
cannot adjust any of the options in the following steps.
•
(Photoshop) Choose Layer > New Adjustment Layer and choose either Levels or Curves. Click OK in the New
Layer dialog box.
Layer dialog box.
2
In the Levels or Curves dialog box, click the Option button.
3
Select Enhance Per Channel Contrast under Algorithms in the Auto Color Correction Options dialog box.