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Chapter 1 An Overview of the Shake User Interface 65
Viewer Script–Superwhite/Subzero: Displays pixel values above 1 or below 0 for float
images. The alpha channel is also tested.
Viewer Script controls (right-click the Viewer Script button to select Load options):
• view: This parameter controls how the pixels are displayed:
per channel: Sets subzero pixels to 0, sets pixels between 0 and 1 to 0.5, and pixels
above 1 to 1. This is applied on a per-channel basis.
per image: Turns subzero pixels black, pixels between 0 and 1 gray, and pixels
above 1 to 1. This is applied across the entire image, so if any channel is beyond 0
or 1, it is indicated.
on Image: Mixes the subzero and superwhite pixels back onto the image. The
colors are controlled with the two color controls.
• SubZero Color: Only active when view is set to “on Image,” it indicates the subzero
pixels.
• SuperWhite Color: Only active when view is set to “on Image,” it indicates the
superwhite pixels.
In this example, do the following:
• Read in the saint_bg.@ from the $HOME/nreal/ Tutorial_Media/Tutorial_05/images
directory.
• Apply an Other–Bytes node and a Color–LogLin node.
• Toggle Bytes from 8 to float.
• Apply the Float View Viewer Script. Since LogLin pushes values above 1, the sky
loses its punch when you go back out to Log and you process the image in only
16 bits.
The per-channel view indicates that most of the superwhite values are in the blue
channel. The per-image view indicates the dark areas more clearly. The on-image
view codes the highlights yellow and the darks blue.
Button Description
Tree Input Log image LogLin (linear) image
per channel float view per image float view on image float view