I recently tried on figure-painting with oil. I first apply a coat of Humbrol's matt black and when I applied the olive-drab oil it simply refused to cover the base colour properly thus created a see-thru effect. Worse still, it took forever to dry and I could't proceed any further with the painting. Have I chosen the wrong oil since it's not branded? I'm feeling hopeless as I thought it shouldn't be too tough to get things done.
