• r-g-gray.tif  Two-dimensional color ramp.  Green ramps up.  Red ramps to the left.  Blue is uniform medium intensity.  Explained below.  This image has a little over 16 bits of color information - 65535 colors.
• r-g-gray-pal.tif Version of above, rendered with a palette of 256 colors by Photoshop*.
• r-g-gray-32colors.tif Version of the 2-D color ramp with 32 colors, chosen by Photogif*.

 

If these gray level images are combined, for example using the 2 & 3 Variable Tool:

Red

Green

Blue

The resulting RGB image or color overlay is this:

2-D color ramp, lots of colors

2-D color ramp, 256 well chosen colors

2-D color ramp, 32 colors