Hex #99d999 or rgb(153,217,153) in RGB space is the tint of green. It has hue angle of 120.00 degrees, value = 85 and saturation = 29. #99d999 can be obtained by mixing 4 colors: 3 drops of yellow, 1 drop of red, 4 drops of cyan, 2 drops of white.
Nearest safe hex - #99cc99. Below you can see the block with #99d999 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #99d999 to the mixer and play with it.