No surface preparation - I was just drawing straight on the oil paper with the sticks. I'm pretty heavy-handed, so that puts down a lot of paint.
Thanks for such a positive response to this one. I'm looking forward to hanging out in the oil forum over here - I'm not very technical about oils, but they are my favourite paints to work with.
The R&F sticks are incredibly soft & make a terrific mess - just my idea of fun! I do also have a few Sennelier sticks. I'm not keen on them, and they don't work well for me on either oil paper or a gessoed surface. I have enjoyed using the Sennelier's on sketch paper, though.