Wicked yellow and detail yellow



I got my requested catalog from Createx. The nice folks sent a how to DVD with the stuff. They also sent their pallet with the colors painted over black and white. Both the wicked and wicked detail yellows when painted over black look green in the picture. I am a bit color blind so this may just be my eyes. Is this true in real life? Does the yellow turn green when painted over black? If so then they are seriously stacking the blue pigments in their black.
yes alot of artist mix back and yellow to get different shades and tones of green especially for landscapes