Manual

188
Image Adjustment
Defi ning “Shadows” and “Highlights”
The Threshold slider in the detailed view of the “Digital DEE” panel determines the bor-
der between shadows and highlights.
Moving the slider to the right or entering a higher value in the Threshold text box in-
creases the range of tones affected by the Shadow adjustment slider and reduces the
range of tones affected by the Highlight adjustment slider.
Try increasing the threshold value if shadow brightness fails to brighten shadows in the
desired tone range, or if highlight adjustment is affecting too great an area.
Moving the slider is to the left or entering a lower value in the Threshold text box in-
creases the range of tones affected by the Highlight Adjustment slider and reduces the
range of tones affected by the Shadow Adjustment slider.
Try decreasing the threshold value if highlight adjustment fails to increase contrast in the
desired tone range, or if shadow brightness is affecting too great an area.
Threshold
Ideally, the threshold for shadow adjustment should be twenty to
forty greater than the highest of the R and G values in the brightest
shadows. The threshold for highlight adjustment should be twenty to
forty less than lowest of the R and G values in the darkest highlights.
To choose a threshold that can be used for both shadows and high-
lights, enter the average of the highest value (R or G) in the brightest
shadows and the lowest value (R or G) in the darkest highlights. Color
values can be determined by moving the cursor over the image and
observing the R and G values in the Information palette.
Shadows
Threshold
Highlights
Tone range affected by
Shadow adjustment
Tone range affected by
Highlight adjustment
1 254
Shadows
Threshold
Highlights
Tone range affected by
Shadow adjustment
Tone range affec ted by
Highlight adjustment
1 254
Threshold slider and
text box