User's Manual

274
ADOBE PHOTOSHOP CS2
User Guide
Correcting images in Photoshop
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 274.
3 Adjust the tonal range.
Begin tonal corrections by adjusting the values of the extreme highlight and shadow pixels in the image, setting an
ove
rall 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. See “Tonal adjustment methods” on page 275.
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
p
roduce special effects.
5 Sharpen the edges of 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
sha
rpening required for an image varies according to the image quality produced by the digital camera or scanner
you use. See “Sharpening images” on page 354.
6 (Optional) Target the image for press characteristics.
Use the Output sliders in the Levels dialog box or the Curves dialog box to bring important details in the highlights
a
nd shadows into the gamut of an output device, like a desktop printer. Do this if your image is being sent out to a
printing press and you know the characteristics of the press.
Becausesharpeningincreases thecontrastofneighboring pixels,it’spossiblethatsomepixelsincriticalareas 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 293.
Color adjustment commands
You can choose from the following color adjustment commands:
Auto Color command Quickly corrects the color balance in an image. Although its name implies an automatic
adjustment, you can fine-tune how the Auto Color command behaves. See “To remove a color cast with Auto Color”
on page 309.
Levels command Adjusts color balance by setting the pixel distribution for individual color channels. See “To use
Levels to correct a color cast” on page 286.
Curves command Provides up to 14 controls points for highlight, midtone, and shadow adjustments for individual
channels. See “About the Curves dialog box” on page 286.
Photo Filter command Makes color adjustments by simulating the effects of photographing with a Kodak Wratten
or Fuji filter in front of a camera lens. See “To change the color balance using the Photo Filter command” on page 298.
Color Balance command Changes the overall mixture of colors in an image. See “To use the Color Balance
command” on page 298.