If you are a traditional oil painter, you want to work "fat over lean":
1)FAT OVER LEAN (addition of medium, such as liquin or galkyd, makes it “fat” and flexible)
2) Thick over thin (Slow drying over fast drying – prevents cracking.)
3) Slow drying over fast drying. Use fast drying colors as under layers.
However, for those of us using cold wax medium with our oils, you do NOT need to worry about fat over lean principles! This
is one of the greatest advantages of working in this medium!