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Chapter 3: Correcting Images in the RGB Color Space 3-5
Setting the Input Range Manually
In both Basic and Expert mode, there are two methods of manually setting the
Input Range:
1. Select the Histograms tab from the Photo RGB Window. You can use the fields
at the bottom of the Input Histogram to enter the Highlight and Shadow densi-
ties, or move the two arrows at the bottom of the Histogram graph. Changing the
RGB Histogram will affect all channels equally. To set each channel separately,
select the appropriate channel from the drop down window and adjust the
Highlight and Shadow points.
Note: In expert mode, any changes to the
Histograms will be shown in the position of the
RGB tone curves.
2. First, perform an Auto Range by clicking on the Auto Range icon within the
Control Bar. Next, select the Pointed cursor from the Control Bar, then click on
the diamond shaped Highlight (white) and Shadow (black) densitometers within
the region, and move them to the desired locations.
Changing the Diffused Highlight and Shadow Point : An Example
It is very important to understand the interaction between the diffused highlight
and shadow point in the image, the diffused highlight and shadow RGB fields in
the Tone and Cast menu, and the highlight and shadow cast correction setting in
the Tone and Cast menu. One will always affect the other.
• The sticky densitometers reflect the exact points of interest.
• The Highlight and Shadow RGB fields control the values those points will
inherit.
• The Cast settings influence how the RGB values react to one another when a
new value is typed into one of the fields or when you select a different cast
setting.
For this example, an IT8 target is used, although a similar target containing a
gray wedge would work as well.