I am in my first DMP process. In order to avoid any posibility of toxic spirits, I start to use Winsor & Newton Winsor Walter mixable oil paints.(my geneva paints are on the way) however they dry very quick over night in room temperature of 20 degree. So next day when I thin the prepared mixed paints with water, they become brighter in their tone. It is really annoying. Any one want to share their experiece to make the paints work better? Appreciate!