Adobe Photoshop CS2
Adjusting Images
Photoshop provides you with techniques to adjust the quality of graphics and photographs. These techniques are especially helpful for images that have been scanned. This document shows you how to adjust images in Photoshop.
Using Auto Levels
Photoshop's Auto Levels feature often provides sufficient adjustment to a poorly scanned image. Auto Levels works by detecting the brightest and darkest pixels and setting them to pure white and black, respectively. Auto Levels can greatly improve contrast in dark or shadowy images.
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From the Image menu, select Adjustments » Auto Levels
The image is adjusted.
Adjusting Shadows
Using the Levels dialog box allows you to change the levels of white and black throughout your image. Your image will change to reflect your new settings as you adjust the levels.
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From the Layers palette, select a layer to adjust
NOTES:
You must adjust the levels for each layer separately.
If the Layers palette is not displayed, from the Window menu, select Layers. -
From the Image menu, select Adjustments » Levels...
The Levels dialog box appears.
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OPTIONAL: In the Levels dialog box, click AUTO
NOTE: This will make a subtle change. If you want a more pronounced change, continue with steps 4-6. - In the Levels dialog box, within the Input Levels section,
- to alter the darkest tones, adjust the left triangle
- to alter middle tones, adjust the middle triangle
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to alter the lightest tones, adjust the right triangle
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Output levels allow you to reduce an image's contrast. On the Levels dialog box, from the Output Levels section, move the left triangle to adjust the image's contrast and the right triangle to adjust the image's highlights
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If you are satisfied with the changes, click OK
If you are not satisfied with the changes, click CANCEL
Adjusting Colors
One way to adjust image colors is by adjusting the hue, saturation, and lightness. Your image will change to reflect your new settings as you adjust the colors.
- Hue distinguishes color by bringing out more of one color than the other (e.g., more green than red)
- Saturation refers to the purity of a color (i.e., the amount of gray in proportion to the hue)
- Lightness refers to how light or dark a color is (i.e., 0% lightness is black, 100% is white)
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Select a layer to adjust
NOTES:
You must adjust the levels for each layer separately.
If the Layers palette is not displayed, from the Window menu, select Layers. -
From the Image menu, select Adjustments » Hue/Saturation...
The Hue/Saturation dialog box appears.
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To adjust all colors, from the Edit pull-down list, select Master
To adjust a specific color, from the Edit pull-down list, make the appropriate selection -
To adjust Hue, drag the triangle to the left or right
OR
In the Hue text box, type a value
HINT: Make sure Preview is selected so that you can view these effects on the image. -
To adjust Saturation, drag the triangle to the left to decrease color intensity, or move the triangle to the right to increase color intensity
OR
In the Saturation text box, type a value -
To adjust Lightness, drag the triangle to the left for added contrast (black) or move the triangle to the right for less contrast (white)
OR
In the Lightness text box, type a value -
OPTIONAL: Select Colorize, which sets the Hue value to 0, the Saturation level to 25, and the Lightness level to 0 that creates an antique-photo quality. Adjusting the top slider will change the color accordingly.
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If you are satisfied with the changes, click OK
If you are not satisfied with the changes, click CANCEL
