Liquid White is one of three Bob Ross Liquid Basecoats essential to the Bob Ross Wet-on-Wet Technique®.  These basecoats (Liquid White/Black) allow us to actually blend and mix colours right on the canvas rather than working ourselves to death on the palette.  The Liquid White/Black/Clear can also be used to thin other colours for application over thicker paints.  The idea that a thin paint will stick to a thick paint is the basis for this entire technique.