While at the Teacher's Seminar at the Jansens, Dave mentioned silk screen painting, which totally intrigued the group. So off he goes to the garage to retrieve some used panels, to better explain what it was.
You start off with Half-tone 1500 dots/inch thin silk fabric, which comes in a roll. This is cut to the size of your pattern, and tacked very tightly into a wooden frame. A chemical (available at the same supplier as the silk fabric) is then applied to the silk fabric, and the whole frame is placed into the dark. Light is what activates the chemical.
Your pattern is either hand-painted with Black on a sheet of acetate, or you could use Photoshop on your computer to fill in the elements using Black, then print it out onto acetate.
Next you take your acetate pattern and place it on top of the chemically treated silk fabric. Place the framed screen on the floor and shine a 150 watt lamp onto the screen for a duration of 30 minutes. You can clamp the lamp onto the edge of the table. The heat of the lamp reacts with the chemical in all the areas, except where the Black painted elements are. Underneath the Black, the silk screen fabric remains porous.
You would then take the screen outside and hose it down with the garden hose to wash off the Black and expose the see-through silk fabric pattern. Very intricate patterns can be painted with this method.
Once the screen is prepared and dry, it can be used repeatedly to apply the basecoat color onto any surface. Just lay the screen over the surface, squirt paint on the end of the screen, then using a special tool, swipe the paint over the surface. This action allows the paint to enter the patterned silk fabric and base the pattern onto the surface below. If you have more than one color to basecoat, prepare two or more screens including only those elements for each color. You could use straight paint, or paint with Faux Finishing Medium to get transparent based elements.
I could see this used for grisaille or underpainting in White or Medium White.
Teachers who have large classes would find this method especially a time saver.