I bought the 15K female enchanters armor. Default green:

Wanted to dye it pink, so I mixed blue+purple+yellow dye=pink. I put it on my undyed armor and I got this grosse yellowish color:

What did I do wrong? Does the default green count as a dye? If so, how do I ever get the nice pink color, as shown for example here (so it IS possible):
But, when I put an unmixed dye on it, purple, it came out perfectly normal (so not purple+green or something):

Please help me out, I want to learn how to bypass the standard of green dye.