About 25 years ago I first was introduced to the wet-on-wet method of oil painting on a TV program hosted by William Alexander. He used a thin, oil based white mixture that he called "Magic White". It was basically, white pigment in linseed oil, about the consistency of cream. He coated the canvas with a very thin coat of his magic white before he began. Bob Ross, Robert Warren, and many others you see on TV were students of William Alexander.
I have made my own version by diluting my titanium white out of the tube with linseed oil. It works just fine.
Tip from: Don
I also make my own fluid clear base coat to prepare a canvas for wet-on-wet painting. I mix some linseed oil and turps half-half, then using a cloth to wipe it onto a canvas. Just a little, don't drown the canvas.
Tip from: Josie L.
Magic White / Liquid White will lighten any colors you use, so are very good for doing the distance on a landscape. It gives you the aerial perspective automatically! Then work the foreground with only a linseed oil medium, to get full color in your next painting session.
Remember, Magic White / Liquid White products are simply a blend of materials to make a medium. They allow oil paint to flow more smoothly, and are very good for the underlayers. They also slow the drying (curing) time of oil paints, so be aware of this. If you do start with either of these products, make sure you do use a medium with any other layers so they will adhere well. I have worked over a Liquid White painting with both linseed and stand oil.
While they do a wonderful job, and I often use them to get a really well done sky, you do not have to use them on the entire painting. Even if you do, you can allow the work to set and go back over them later with other layers.
Tip from Susan Tschantz