Adobe Photoshop CS3 - Manual (Page 164)

PHOTOSHOP CS3
User Guide
157
• Duplicate or make a copy of the image file. Working on a copy of your image preserves the original in the event
you need to use the image in its original state.
• Remove any flaws such as dust spots, blemishes, and scratches from the image before making color and tonal
adjustments.
• Plan to use adjustment layers to adjust the tonal range and color balance of your image rather than applying an
adjustment directly to the image layer itself. Adjustment layers let you go back and make successive tonal adjust-
ments without discarding data from the image layer. Keep in mind that using adjustment layers adds to the file
size of the image and demands more RAM from your computer.
• Open the Info or Histogram palette in Expanded view. As you evaluate and correct the image, both palettes display
invaluable feedback on your adjustments.
• You can make a selection or use a mask to confine your color and tonal adjustments to part of an image. Another
way to apply color and tonal adjustments selectively is to set up your document with image components on
different layers. Color and tonal adjustments are applied to only one layer at a time and affect only the image
components on the targeted layer.
Correcting images
Here is the general workflow you follow when you correct the tonality and color of an image:
1 Use the histogram to check the quality and tonal range of the image.
2 Adjust the color balance to remove unwanted color casts or to correct oversaturated or undersaturated colors. See
“Color adjustment commands” on page 158.
3 Adjust the tonal range, using either the Levels or Curves dialog box.
Begin tonal corrections by adjusting the values of the extreme highlight and shadow pixels in the image, setting an
overall tonal range for the image. This process is known as setting the highlights and shadows or setting the white and
black points. Setting the highlights and shadows typically redistributes the midtone pixels appropriately. However,
you may need to adjust your midtones manually.
To adjust the tonality in just shadow and highlight areas, use the Shadow/Highlight command. See “Improve shadow
and highlight detail” on page 171.
4 (Optional) Make other color adjustments.
After you correct the overall color balance of your image, you can make optional adjustments to enhance colors or
produce special effects.
5 Sharpen the edges in the image.
As one of the final steps, use the Unsharp Mask filter to sharpen the clarity of edges in the image. The amount of
sharpening required for an image varies according to the image quality produced by the digital camera or scanner
you use. See “Sharpen images” on page 207.
6 (Optional) Target the image for press characteristics.
If are sending your image to a printing press, and you know the characteristics of the press, you can use options in
the Levels dialog box or Curves dialog box to import highlight and shadow information into the gamut of an output
device, like a desktop printer.
Because sharpening increases the contrast of neighboring pixels, it’s possible that some pixels in critical areas might
become unprintable on the press that you’re using. For this reason, it’s best to fine-tune the output settings after
sharpening. For more information on adjusting the output settings, see “Setting highlight and shadow target values”
on page 174.