1.5

Scale RGB
Expands or contracts the overall contrast ratio of a shot, from the black point to the white
point, centering the midpoint of this operation at a percentage of image tonality that
you specify. This node has two parameters:
• Scale: The amount by which to expand or contract the overall contrast ratio in the shot.
This is a multiplicative operation, so a value of 1 produces no change, while larger
values increase the contrast ratio, and smaller values decrease the contrast ratio.
• Center: Specifies the percentage of image tonality upon which the expansion and
contraction is centered, so the original image values at this percentage remain at that
percentage. The default value of 0.5 adjusts the white and black points equally in both
directions (the white point goes up, the black point goes down, and whatever values
are at 50 percent remain at 50 percent). A value of 0 pins the black point while applying
the entire adjustment to the white point, and a value of 1 pins the white point while
applying the entire adjustment to the black point.
Sharpen
Applies a Sharpen Convolution filter that selectively enhances contrast in areas of image
detail to provide the illusion of sharpness. Should be used sparingly as this operation also
increases the sharpness of film grain and video noise. This node has one parameter:
• Sharpen: Higher values increase image detail contrast. A value of 0 does no sharpening.
Smooth Step
Applies a nonadjustable “s-curve” adjustment to slightly crush the blacks and boost the
whites, leaving the black and white points pinned at 0 and 100 percent. Designed to
emulate the exposure tendencies of film at the “toe” and “shoulder” of the image. This
is a similar contrast adjustment to that made by the Film Look node.
Stretch
Provides separate vertical and horizontal scaling operations that let you “squeeze” and
“stretch” the image. You can change the center pixel at which this scaling is performed.
This node has four parameters:
• Horizontal Center: The pixel at which horizontal scaling is centered. The center pixel
doesn’t move; instead, the scaling of the image is relative to this position.
• Vertical Center: The pixel at which vertical scaling is centered. The center pixel doesn’t
move; instead, the scaling of the image is relative to this position.
• Horizontal Scale: Specifies how much to stretch the image, horizontally. Higher values
stretch the image outward, while lower values squeeze the image inward. The default
value at which the image is unchanged is 1.
• Vertical Scale: Specifies how much to stretch the image, vertically. Higher values stretch
the image outward, while lower values squeeze the image inward. The default value
at which the image is unchanged is 1.
309Chapter 11 The Color FX Room