To set target values using the eyedroppers – Adobe Photoshop CS4 User Manual
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USING PHOTOSHOP CS4
Color and tonal adjustments
Last updated 1/10/2010
Targeting shadows and highlights with Output Levels sliders
To set target values using the eyedroppers
1
Select the Eyedropper tool
in the toolbox. You can choose 3 by 3 Average from the Sample Size menu in the
Eyedropper tool options. This ensures a representative sample of an area rather than the value of a single screen
pixel.
2
Click the Levels
or Curves icon
in the Adjustments panel.
When you select Levels or Curves, the Eyedropper tool
is active outside the dialog box. You still have access to the
scroll controls, the Hand tool, and the Zoom tool
through keyboard shortcuts.
3
Do one of the following to identify areas of highlights and shadows that you want to preserve in the image:
•
Move the pointer around the image, and look at the Info panel to find the lightest and darkest areas that you want
preserved (not clipped to pure black or white). (See “
•
Drag the pointer in the image, and look at Curves in the Adjustments panel box to find the lightest and darkest
points you want to preserve. This method does not work if the Curves adjustment is set to the CMYK composite
channel.
When identifying the lightest highlight details that you want targeted to a printable (lower) value, don’t include
specular highlights. Specular highlights such as the highlight glint in jewelry or a spot of glare are meant to be the
brightest points in an image. It’s desirable to clip specular highlight pixels (pure white, no detail) so that no ink is
printed on the paper.
You can also use the Threshold command to identify representative highlights and shadows before accessing Levels or
Curves. (See “
Create a two-valued black and white image
194.)
4
To assign highlight values to the lightest area of the image, double-click the Set White Point Eyedropper tool
in the Levels or Curves adjustment to display the Color Picker. Enter the values you want to assign to the lightest
area in the image, and click
OK. Then click the highlight you identified in step
3.
If you accidentally click the wrong highlight, click the Reset button
in the Adjustments panel.
Depending on the output device, you can achieve a good highlight in an average-key image using CMYK values of 5,
3, 3, and 0, respectively, when you are printing on white paper. An approximate RGB equivalent is 244, 244, 244, and
an approximate grayscale equivalent is a 4% dot. You can approximate these target values quickly by entering 96 in the
Brightness (B) box under the HSB area of the Color Picker.