Hex #808b00 or rgb(128,139,0) in RGB space is the tint of yellow. It has hue angle of 64.75 degrees, value = 55 and saturation = 100. #808b00 can be obtained by mixing 4 colors: 2 drops of yellow, 1 drop of red, 2 drops of green, 1 drop of black.
Nearest safe hex - #999900. Below you can see the block with #808b00 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #808b00 to the mixer and play with it.