Sabrina Color Models

Sabrina works with a snall number of basic colors, such as green, red, blue, etc., and a a number of shades, or intentsities, of these colors. The color of a pixel in a ray-traced rendering is determined by the color assigned to the cell that the ray intersects. The shade of that color depends on the angle the ray makes with the surface. The intensity darkens as the angle increases.

Sabrina recognizes the color capability of the display, from 2 bit monochrome to 24 bit TrueColor.

Monochrome (2 colors) Displays

Only Etch images and Line Drawings are allowed; Color ray tracing is not permitted.

PseudoColor(16 to 226 Colors) Displays

Sabrina createsa color map using as many shades of each (8 or 4) basic color as can be accomodated by the total number of colors available. The user can control the size of the color map.

Sabrina color palette for an 8 Plane PseudoColor display.

HighColor (>256 Colors) to TrueColor (24 bit or more) Displays

Sabrina assumes the system will faithfully represent each requested color. The exact color of each pixel is specified.

Sabrina color palette for a TrueColor display.

Comparison of Color Models

Distinct shading bands may be visible on curved surfaces in the PseudoColor model, especially when a large number of basic colors are used. Consider the 8 plane PseudoColor and TrueColor images of the superconducting supercollider particle detector.

PseudoColor images without shading bands may result from defining only a few (2 or 3) basic colors.

Default Basic Colors

The basic colors defined by default depends on the number of color planes (or, equivalently, the number of colors = 2planes). An 'X' in the table means the basic color is defined. The Red-Green-Blue components range from 0 (off) to 1 (full intensity).
Color Planes
ColorRedGreenBlue468> 8
White 1 1 1 XXXX
Red 1 0 0 XXXX
Green 0 1 0 XXXX
Purple 0 1 1 XXXX
Blue 0 0 1  XXX
Magenta 1 0 1  XXX
Yellow 1 1 0  XXX
Black 0 0 0  XXX
Brown 0.7 0.5 0.3    X
Orange 1 0.6 0    X
Pink 1 0.8 0.8    X
LightRed1 0.6 0.6    X
Gray 0.7 0.7 0.7    X
DarkGray0.5 0.5 0.5    X
DrkGreen0 0.75 0    X
Violet 0.8 0 1    X


White Rock Science Logo Last modified: September, 2004
Kenneth A. Van Riper / email