Originally Posted by JamieWG
It really depends on what your medium is and how you work. If it's opacity you're looking for in the cad yellow, nothing else is going to be as opaque and have that kind of chroma and tinting strength. It's a lot easier to make a substitution for cad red, since it's a darker color. The opacity isn't as big an issue.
bismuth vanadite (Schmicnke have it) is suitable opaque but very green yellow. and py65 is really nice colour actually one my basic yellows today. anothers are py35 (i still use it) and py3. but i trying replace them something py154 or py184. (i dont remember exact number). but budget reasons i also going avoid cadmiums later but art supply budget maybe soon drop... ps. to me w&n artist quality aquarelle have good colours avoid cadmiums. but in student stuff to me almost allways yellows are too weak even when i dont try replace cadmiums with them.