I used to waste oodles of time blocking in my plein air paintings until I finally learned some great tips for doing them fast, such as skipping the drawing, establishing the value range first, and addressing each set of values in a logical order. Here’s how I do them now, which takes only about 10-15 minutes.
1. I prefer to work on a white canvas when I’m en plein air because I believe it allows more light to bounce off and through the painting, giving it a lighter, fresher look. Using a smallish brush and a medium-valued green paint mixture, I quickly sketch in the bare bones of the big shapes. Mostly I just want to position my horizon line correctly and mark the placement of a few important shapes. In this outdoor painting, I decided to use value contrast to draw your attention to the focal area, and so I start by laying in my lightest light value. Since the morning light was warm, I’m using a light, warm yellow-green.
2. Next comes my darkest dark. I might as well use a little color contrast against the yellow-green, so I make that dark green a little on the purple side. Already the lightest and darkest values in my value range are established, as is my focal area. Next, I want to continue putting in my dark values to the right of the darkest dark, but notice how I made that area slightly lighter in value. And if I have warm light, then I must have cool shadows, so I also make that shape cool in color.
3. Now it’s time to move up a notch to the medium values. Looking at my subject I see some across the surface of the water, so I paint those on either side of the reflection of the tree. Notice that I’m pretty loose and almost sloppy with my paint. I don’t even bother to thoroughly mix my colors, which gives each shape some slight variations. That’s fine. The purpose of the block-in is mostly just to cover the canvas with paint in the correct values.
4. Continuing to move up the value scale, I go a little lighter still. But notice that I make the shadowed sides of the trees on the far right in a cool medium-light green, and I make the far left tree and river bank a warmer yellow-green because these are touched by the sun. The river bank shape is quite large and needs to be subdivided somehow, so I make a slightly darker, cooler shape in the lower portion of the big shape.
5. All that’s left is the sky color. I started off with a dull blue, which I laid over the water’s surface. But as I went to put that same color up in the sky shape, it occurred to me that maybe I should make it a more yellow sky to suggest the morning sun. So I put that in, too. This is partly what a block-in is for: to experiment with different colors to see what will work best for the mood and harmony of the painting. Having done this, though, I realized that my sky value was about the same as my focal area tree. To maintain that big tree shape as the lightest light, I went in with an even lighter yellow-green over the uppermost portion of the tree.
To me, this is a block-in that does its’ job quite well. The shapes are positioned well on the canvas, the values are just what I had planned for to highlight my chosen focal area, and the colors are already accurate in their suggestion of warm light and cool shadows. What do you think?