Thank you so much Michael for your help! I will do as you suggested. I think I will sand the unwanted color out, to be on the safe side, rather than painting on top of it.
I did my underpainting over several sessions. The first was just pure mixed paint (raw umber + white). All the sessions after that, I would brush a thin layer of Galkyd over the area that I was going to paint, before painting over it (raw umber + white + medium). However, my problem was that the area where I brushed the medium on got so tacky, and I hardly have time to put the paint on properly. I don't know where I have gone wrong. The medium that I used to use for my direct painting was 1/3 stand oil + 2/3 turpentine and it worked really well with my painting speed.
Also, the reason why I want to paint over it is because I don't know if I can continue glazing it (if I get rid of the bumpy parts like above). Is there a way to continue glazing the painting, or my only choice right now is direct painting over it?
Thank you Michael for your time replying my post.
Mai
