How do I find my colors for setColorTransform?

OK this is probably a dumb question. I have my first color from some code I found, so I did a screencap & sampled it in PhotoShop to get the hex color for the color chip that changes my grayscale bitmap to that color on rollover.

myColorTransform.ra = 50;
myColorTransform.rb = 244;
myColorTransform.ga = 40;
myColorTransform.gb = 112;
myColorTransform.ba = 12;
myColorTransform.bb = 90;
myColorTransform.aa = 40;
myColorTransform.ab = 70;

hex is about #f9c480 and I’m cool with my first accidental color. But how do I get more colors. How to start with a hex color and figure out what to put for rb, ga, ba, etc?