Someone at Wetcanvas asked about how to do an alcohol wash underpainting so I wanted to share my answer here also...
I start out with a preliminary, pretty basic sketch on my board with a charcoal stick and then put down the first layer of color in pastels.
This is my first, preliminary layer of pastel.....I'll explain starting with the sky. I normally use a dark value of blue at the top of the sky, then in the middle sky a medium (lighter than the dark) value, and then at closest to the horrizon or in this case tops of the trees with the lightest value of blue. It almost looks like 3 stripes.
Then I block in the darkest value for all of the trees in the background. In this painting, I used a Mount Vision extremely dark navy blue.
Then in the foreground I use the same blues as the sky for the snow, but in reverse order. The lightest will be the farthest away; the medium will be in the middle; and the darkest will be in the foreground.
That covers all of the board and I've only used 4 colors.
Then I take a cup and put about an inch of rubbing alcohol in it and with a flat, synthetic square paint brush (about a 1/2" wide) I get it wet with the alcohol and starting at the top using crosshatching motions, start to liquify the darkest blue (MAKING SURE THE BRUSH IS NOT DRIPPING WET!!), I keep cleaning the brush by swishing it in the alcohol and then move down to the medium value blue and start liquifying that area, but now I'm starting to bring that medium value up into the dark value so the stripes disappear. Again, swishing off the brush to clean it, I go into the lightest area and also crosshatching and blending it into the medium value. When that is done, I have a nicely blended sky that is soft and has a nice transition from lightest at the tree line to darkest at the top, but there are no hard lines and no longer any stripes. Sometimes no other layers of pastels are necessary if the sky turns out really nice using the alcohol, so I just leave it just the way it is. I love it when that happens
Then I wet my brush again and because trees are vertical, I use vertical strokes with the alcohol until that is all liquified.
Then in the background all the way to the foreground I repeat the steps I took in the sky, but using more horrizontal strokes.
In the end all of the first layer of pastel is liquified and is no longer clogging the tooth.
I know that when other artists use this type of method, they let it drip, but I don't! That's just my style.