How to Paint Plein Air
Step by Step
Artist Randy Pitts
Color for Palette:
First thing is my color choice for the palette (note almost always one can mix colors for any occasion) I essentially choose to use a primary palette with a warm and cool values. The pallete consist of primaries and two earth colors in addition adding a white. I supplement this to experiment or if there is a specific need thats can’t obtain with my standard configuration. This palette won’t create intense bright purples, like in flowers for instance.
Colors: Titanium White, Hansa Yellow Deep, Cadmium Lemon Yellow, Naphthol Red, Alizarin Crimson permanent, Ultarmarine Blue, Cobalt Blue, Yellow Ochre and Transparent Oxide Red.
Please note that while this is from my own photo reference, I use the same approach outside as I do in the studio.
Step One:
I use thinned Transparent Oxide Red to draw out the basic shapes of the painting, suggesting secondary shapes where I think I need them to guide me later. Outdoors, when the sun is bright, white canvas can be hard on the eyes, even in shade, so I will often tone the canvas with a wash of Transparent Oxide Red to kill the white of the canvas before starting. A wash that’s been wiped down will set up pretty quick outside so you can begin painting over it after a few minutes. Since I’m in a controlled lighting environment for this painting, I opted to start with the drawing and not toning the canvas. 
Step Two:
Placing Values:
Next place in the dark values. Unfortunately, the photo does not show the difference in color temperature of the different darks I’ve placed. While the values are almost identical, the darks in the bottom foreground are warmer than the darks in the middle ground trees, which are cooler. While the darks look almost black, they are not. This will become apparent when color is added.
Step Three:
Working back to front:
I begin by blocking in the major shapes of the sky, and the mountains. Notice I use simple color notes for the large overall shapes of the mountains. I’m looking for what the overall color of each area looks like to me when I squint at the subject and paint that color. I’m not interested in detail at this point. I’ve also covered up my tree darks some. That’s okay, they’ll be restated later. Mixtures of the distance are mostly White, Ultramarine Blue, and Alizarin Crimson. Varying the value by adding more white for the distant peaks and less white for the peaks closer. The peaks will come forward, mixture has more Alizarin color, and then the closest one are showing more green because of tree cover. These shades are subtle and how this is achieved is by using the knowledge of the color wheel to “bend” or “gray” colors by adding the complementary color to the mixture. For instance, If the purple of the distant mountains is reading too intense, adding tiny amount of its complement, yellow, will help to tone down the intensity. This is key in making colors read correctly in distance. To make the greens grayer, add red.
The colors with shorter wave lengths in the light spectrum. For example: Yellow and Red, their influence on the landscape drops as we recede into distance. That’s one of the reasons why the distant peaks appear bluer and cooler.
This is the time to discuss relative color temperature. It’s obvious that blue is cooler than yellow. Colors can appear “warmer” or “cooler” in relation to the color next to it. For example: in the image, the most distant mountain peaks are cooler than the mountains just in front of them, even though both would be considered cooler than the peak in front of them.
You can have a red, that’s considered a “warm” color by itself but next to an orange or yellow, it could be considered cooler, therefore it’s RELATIVE to the color it’s next to. In general, as colors come nearer to the viewer in a landscape, the warmer they appear.
Finally, you will notice how within the lines created by where the mountains meet the sky, I’ve adjusted some of the edges along those lines. By softening some of the edges and leaving others harder, this helps create the illusion of atmosphere and depth.
Step Four:
Blocking in the foreground.
When painting what I see as the color notes of the major shapes of the ground plane, river and riverbank. You can begin to see how the grassy areas have more yellow in the foreground as opposed to those in the distance. No need to worry about detail, just major shapes and color notes. Detail comes later!
The great landscape painter; John F. Carlson, noted as the four planes of light in the landscape.
Typically, since it is the source of the light,
1.Lightest area in a landscape is the sky.
2. Lightest area is the ground plane because it’s the area that receives the most light upon it.
3. Areas receiving less light are the angled planes of the mountains.
4. Darkest areas are the uprights, such as tress and bushes.
The one exception to the rule in this painting, because there will be a very bright reflection of sunlight within the water of the river. Otherwise the four planes of light holds true! Now that the canvas is almost completely covered, I assess what I’ve done with the colors values, temperature (Intensity) to make sure they are accurate, or if I need to make adjustments in an area.
Step Five
Details
Details to the mountain’s Recommended advice: “work all over the canvas,” during this stage. Sound advice, but I continued working back to front because of the trees in the mid ground. One way isn’t better than the other, it’s just what felt logical to me for this particular piece.
Detail is nothing more than adding smaller and varied color notes on top of the larger shapes. I recommend detail by applying subtle color notes, define the characteristics slopes and where light hits. I don’t try and render every tree or rock. I think this where many people lose a painting because when you add too much, the painting becomes flat. We don’t see every tree on a slope or every rock, but rather the shapes they suggest!
Nothing is blended here except along some edges. Addtional method used is loading a brush and making a stroke, allowing the paint to blend toward the end within lessening brush pressure. The paint brush-load lessens the pressure is lifted, Paint will mix as the stroke tapers off. No need for going over. Many novices wind up grinding paint into the layers below in an attempt to make something smooth and really all they achieve is a muddy painting. In my opinion, the less you have to mess with a stroke applied, the better the end result.
Step Sixth:
Adding details to the river.
Here I define the exposed river bed and the river. There was a lot of sun reflecting off the water, which appears almost white. It isn’t. Light is painted using white and Hansa Yellow added to it. The mix on my palette was a light, but bright yellow. It’s amazing how “white” it looks next to everything else. This may be an area I revisit. My objective is color more intense. Still, it’s more yellow than it shows here. I added some very bright sparkles to add to the feeling of the light reflecting off the water. When working with paint that has a lot of white in it, you have to use a very light touch and a lot of paint, especially working wet on wet. If you don’t, the paint underneath gets picked up immediately and dulls the brightness. This can be used to your advantage in certain situations. but not here! It’s why I left the canvas bare where the light paint was applied. The river bed was essentially gravel piled up by the flow of the river. Instead of trying to paint individually rocks, I painted color variations. I think it gets the “feel” of the gravel instead trying to render a pile of stones. My choice to work on this area next is because the ground plane on either side of the river rests on top of this river bed. This way I can work down to it and keep the sense these areas are slightly higher!
Step Seven
Here I’ve gone back in and re-stated the pine trees in the middle distance and added the suggestion of bushes and smaller trees as well. These were backlit! This is merely the suggestion of tree shapes. I didn’t care for how I had painted the mountain on the right, so I wiped it out and restated and added detail.
The Finale: Here is the final painting. The color is more accurate here than in previous photos. I added some mid tones into the ground plane to the left and right to suggest areas where there are variations in the grasses then applied the bright green around and on top. As the grasses come forward notice they are brighter and warmer. The shadows have some warm and cool dark tones added for variety. In the middle distance Lights added to where the dirt is noted by the sunlight and painted some variety of subtle blues/ grays shadows. In the mid ground trees there are some suggestions of light along the edge of trees like you would see when they’re back lit. Notice again how no detailed individual blades of grass painted but, rather suggested by brush strokes and variations of color. What I’m after is the feeling of light hitting the tops of the grasses and what your eye would see observing it.
Questions to ask yourself while painting!
How do you know it’s done? When you back away and look from a distance, if the painting is accomplishing what you set out to do, and there’s no glaring errors, you’re done. Ask yourself these questions:
1. Does the painting “read” correctly? This just means does the whole thing hold together when you look at it.
2. How are the values? If your values are correct the painting will read correctly. Value is almost of higher importance than color. If you can get the values correct, the color can be off slightly but the painting will still work. This is not saying color is unimportant. Just that value is critical to a painting’s success!
3. Do my colors convey what I want the mood of the painting to say to the viewer?
4. Is there a focal point? I preferred the scene radiated out from a central point. It’s not blatantly obvious, but everything guides your eye where the bases of the mountains converge, which is where the town is if you could see it.
5. Is there harmony? Do all of the colors relate to one another. One of the good things about using a limited palette where you have to mix colors is the fact that almost all of the color mixes have at least one or more of the palette colors within them. This builds the harmony in almost automatically.
Artist don’t always use enough paint. In order for your painting to grow and develope you will probably waste paint. Having thicker passages of paint adds variety and texture. Don’t be afraid of your supplies. You can’t be brave in your approach if you’re worrying about the coast or mistakes. We learn and develop through our mistakes.