I start with a nice input image of some flowers on my prickly pear cactus:
I then generate a "color-magnitude" diagram for some configurations:
The left two panels show R on the x-axis, and G-B on the y-axis. The white line separating the two panels vertically represents a value of zero. So pixels appearing above the white line have a positive G-B value, and those below the white line have a negative G-B value. The middle two panels show G versus R-B. The right panels show B versus R-G. The colors of each pixel correspond to their colors in the input image. The x-axis range is 0 to +255 (left to right). The y-axis range is -255 to +255 (bottom to top).
Here's another example, using the image of the Earth taken by Artemis II:
Here's R vs G-B, G vs R-B, and B vs R-G
clearly picks out landmasses, ocean, clouds, and aurorae!
