If you are using air brush paints. I would suggest checking this site out. I used it to color match the green playfield on a Bally Eight ball I just restored. I used the paints from the company and it worked fine. You can check my post to see how the color came out.
https://pinside.com/pinball/forum/topic/bally-eight-ball-restoration-for-charity-event
"Using the Golden Paints Image matcher found on their website (http://www.goldenpaints.com/mixer), I was able to get a great match on the first try. I used pipettes for each color and measured the amounts of paint into my airbrush bottle. I mixed the paint by hand and loaded the airbrush. A little testing and I was on my way to painting."
Mike