I have been experimenting with colors of lights. I found that I sometimes would get to a point where I would say to myself, "If I could select a color between these 2 colors, it would be just right."
I found this web site where you can do just that:
https://meyerweb.com/eric/tools/color-blend/#:::rgbdFP uses RGB colors. The RGB option on this site requires that you separate the RGB numbers with commas like this: 255, 60, 21
Sometimes I find say to myself, "I would like to add more green or red to this color." You can do this also but you need to know the standard RGB values for named colors. I have listed them here:
Red 255, 0, 0
Green 0, 128, 0
Blue 0, 0, 255
Purple 128, 0, 128
Yellow 255, 255, 0
Orange 255, 165, 0 (Some sites say it is 255, 128, 0. You can try both.)
The site has a handy option called "Midpoints". If you select "1", it will list the 2 colors you entered with the mixed color in between. Entering a higher number will produce a gradient with different mixes of the 2 colors. If you need more gradients than what the 10 color option provides, you can replace "Color1" or "Color2" with one of the colors in the "Palette" list.
MORE ADVANCED OPTION
To make a color darker, you can just use the slider to add more black but you can mix a complementary color also. Artists tend to mix a complement to a chosen color because it produces a richer color. A complementary color is the color directly opposite a color on the color wheel. I found this site that gives you the complementary color for any color you select (use the option for "Complementary" and not "Split Complementary"). Then you can use the Color Blender site to mix the complementary color to your selected color.
This site provides a calculator that identifies complementary colors along with some other matching color options:
https://www.rapidtables.com/web/color/color-wheel.htmlGeorge