I've noticed, in videos, that painters sometimes dip their brush into some kind of liquid then go for their color. My paints are in jars with the slow dry medium already mixed in. If I wanted to thin the paint, can I use more slow dry medium? Or should I use linseed oil or ? I didn't see this mentioned in Mark's videos.
I watched a 3 hour video of, forget his name, an artist painting John Singer Sargent's Lady Agnew, and he often added something to his paint to make it more of a wash. Or maybe I misunderstood. I'm so new to all or this!