Operation Manual

To adjust the midtone levels in an image
Do one of the following:
µ
Drag the Gray Levels slider until the brightness values in the image’s midtones are correct.
Gray Levels slider
µ
By default, the gray point is set to 0.50. Select the number in the Gray (G) field, then enter
a value from 0.02 to 0.98 to correct the brightness values in the image’s midtones.
Showing Quarter-Tone Levels Controls
When you need additional control over tonal values between the midtones and shadows
as well as the midtones and highlights, you use the Quarter-Tone Levels controls in the
Levels area of the Adjustments inspector or the Adjustments pane of the Inspector HUD.
For example, if you need to add contrast to the midtone values independently of the
black and white point settings, you use the Quarter-Tone Levels sliders. Unlike the Black
Levels and White Levels sliders, Quarter-Tone Levels sliders are independent and affect
only the tonal range of the pixels they represent: either shadows to midtones or midtones
to highlights.
To show the Quarter-Tone Levels controls
µ
Click the Quarter-Tone Controls button.
Click the Quarter-Tone
Controls button to
show the Quarter-Tone
Levels sliders.
Adjusting the Brightness of an Image
You can also use the Levels adjustment controls to adjust the brightness of an image.
When you adjust the brightness of the image, the Black Levels, Gray Levels, and White
Levels sliders modify the tonality of the image based on the new brightness value.
Adjusting Brightness Uniformly with the Brightness Levels Slider
You use the center Brightness Levels slider at the top of the Levels histogram to uniformly
adjust the brightness of the image.
561Chapter 17 Making Image Adjustments