“It is much easier to paint a sky to suit a landscape than a landscape to suit a sky.”
Sir Alfred East, The Art of Landscape Painting in Oil Colour (1915).
When should you paint the sky? Should it be the first thing you paint when you begin a landscape painting? The last? All at once? Incrementally?
Some of you may have heard the oft repeated advice to paint the sky first. The argument for this approach goes: The sky sets the key for the landscape , the value range for the landscape, the mood of your picture, and the light condition you wish to depict. And, painting back to front, helps with edges too. All of these things are true. But, there are also good reasons not to!
Here is why. Most beginners and many intermediate painters will start out by keying their sky too dark. The sky is generally the lightest plane in the landscape and on a typical sunny day its value might range from 9 to 7.5 or 8. Very often, without any other value to compare it to on the canvas, students will mix a value range which is one or even two to three value steps darker than what it should be! As a result, every other value in the landscape gets pushed toward the darker side of the value scale. The result is usually a dark painting, or one where the values are all in the middle of the range as the student struggles to keep things from getting too dark.
It is much easier to judge the value of your sky once you have something to compare it to. Ideally, you will use a value scale to mix your color and make sure it is in the correct range. But, you also want to compare it to other values. So, laying in a range of values, including your lightest light and your darks will help you judge the correct value for your sky.
Secondly, As Sir Alfred East notes, one of the challenges in landscape painting is to make the sky and the landscape work together harmoniously. There are many more “moving parts” – value changes, temperature shifts, drawing issues, color harmony to solve in the landscape and they need to be worked out to some degree before you can effectively “marry” the sky and the landscape.
However, painting back to front does have real advantages and being aware of and careful about your sky values can solve some of the problems I have outlined above.
This is why that I recommend students lay in an initial thin layer of opaque pigment at a value of about 9, after completing the initial underpainting or lay in of their composition. Think of this as a “placeholder” value and color which will help you keep your painting in the correct key. Then, as you develop your painting, and have established the darkest and lightest tones of the value range you intend to use, you can go back and finish your sky.
You can read more about Sir Alfred East and his book in this post.