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Reference: Preferences
Sample Point Size
This setting determines the size of the area sampled when dis-
playing the color value for the pixel under the cursor in the
information window, or when the white-point, gray-point, and
black-point tools are used in the Curves palette. You can select
a sample sizes of 1
×
1, 3
×
3, and 5
×
5 pixels. When the sample
size is set to 3
×
3 or 5
×
5 pixels, the average for the pixels
sampled is used. Choosing a large sample size reduces preci-
sion, but also minimizes the effects of noise; choosing a small
sample size has the opposite effect.
Auto Contrast Calculations
A further option in the Color sheet allows you to specify how
auto contrast operations in the Curves and LCH Editor pal-
ettes calculate the input values for the white point and black
point. By default, the white point is set to a value that excludes
0.5% of the brightest pixels in the current crop, the black point
to a value that excludes 0.5% of the darkest pixels in the crop.
This produces an optimal dynamic range, with minimum loss of
detail in shadows and highlights. To preserve detail at the ex-
pense of dynamic range, lower the “excluded” value for auto
contrast (a value of zero will set the black and white point re-
spectively to the darkest and brightest pixel in the crop). To
increase the dynamic range at the expense of detail, raise the
“excluded” value.
Scan Window Settings
The Preview Tab
Using the Preview tab, you can select the settings that will auto-
matically be applied to images when the
Preview
button is
clicked.
