Above is the second in a series I'm painting from my trip to Colorado last September. I'm going to post this completed painting by itself for the moment, but will add a couple shots I took earlier in the process. It will help demonstrate a cool blocking-in idea Laurel came up with for our alla prima class. For lack of an established name, I refer to it as the "rub in, rub out" technique. Stay tuned. . . .
Okay, here is a snapshot of the completed block-in. It's all done using a dark neutral, a large brush, paper towels and linseed oil. The linseed oil is used to allow the paint to spread more easily, the large brush to get the canvas covered more quickly and to keep you from getting too detailed. The paper towel is used to rub off excess paint from areas on the canvas that have lighter values than what has been applied with the dark neutral.
So, to begin with, start placing the main, simplified shapes on the canvas in their correct location on the canvas. One cool thing about this process is it's very low pressure. If you don't like where you applied your dark neutral, or you applied too much, just rub out the necessary areas with paper towel, and rub in with your brush the areas that need to be darker. Any dark neutral that remains on the canvas will just add punch to the shadow areas.
To make it easier for the dark neutral to spread easily, dip a paper towel in linseed oil and scrub a thin amount of the dark neutral into the canvas. Do be careful not to make the underpainting runny or to use so much oil that the canvas gets shiny reflections. If this happens, use paper towels to pick up the excess.
Continue applying and removing the dark neutral until you have a good value map that is accurate in the placement and also in creating an accurate range of values on the canvas before adding color.
Now you're ready to start putting in color. Paint in the main color masses, blended in on top of the dark neutral underpainting, and continue until, finally, you've added in the all the highlights and everything looks the way you dreamed it would.