16,777,216 colors possible.
Your perception of a color is affected by the colors near it.
A bit of code here to demonstrate the potential of color relationships using Processing.
Note what happens to your own color perception as you play with this program.
No longer thinking in standard RGB color profiles, we reframe our thought processes to use a more advanced color mode for rendering hues, HSB. (There is a basic overview of RGB color and the pixel grid system posted here if you need a primer.) Simply put, HSB gives you a more refined way to control how you think about coding your colors.
As a method of programming colors, using HSB is useful for creating color progressions (such as gradual palettes of related colors). In this case, knowing the actual figures for the red, green and blue primaries (RGB) is not necessary. HSB offers a more intuitive representation of the relationship between colors. Just find your color number (H) and then gradually adjust the saturation (S) and brightness (B) values for smooth incremental colors.
It is important to note that HSB is the exact same set of colors as in the RGB color space.
HSB just uses a different coordinate system to describe the colors.
The Color Spectrum
Use this interactive program to explore gradations in color.
Note your perceptions of contrast, light and scale.
The Color Wheel and Exporting
This program provides a closer look at how HSB color mode functions. While the program runs, pressing the number keys 1-5 will redivide the color wheel and generate more complex divisions. When you press S, the program will export a PNG image of your Sketch to the corresponding code folder.
Download and play with the annotated code here –> Color_Wheel_Code