Perhaps the most useful technique by watercolor plein-air artists.
This technique allow you to complete a painting on-site without getting bugged down by details or with too many glazes. Theoretically, you can complete within 3 layers. However, apart from time constraint, there aren't any rules to why you should limit yourself to just 3 layers. Bear in mind that this method is most appropriate when you use fresh pigment from a tube..
Here's how you work the magic. By the way, I am demonstrating with just two colors. Why ? Because beginners too often have problem managing colors . If you can't even work with 2 ? Reduce it to one. There's no prize for the artists who uses most colors.
At the most fundamental level, one just need to ensure that that the correct sense of color temperature is in place. Excessive colors rarely enhance an image when the temperature shift is nothing but a chaos.
Important things to remember when painting:
Shapes + Composition (Simplification and design is key. It is literally impossible to paint everything)
Value structure / Good drawing / Chiaroscuro (extremely important for watercolor since it rely extensively on light versus dark dramatic structure )
Soft versus hard edges
Color temperature (warm versus cool) . There is no need to score accurate color. A painter merely depict a color's relationship to its surrounding. e.g does the color have more warmth (Red or orange) or cool (Green or blue) in it ?
Think about the density of tea, milk or cream to assess how thick or thin your paints are. Maximum coverage is made with the thinnest layer, mid tone and shadow mass are all connected with milk layer and details are left in for for thickest coat of paint. (error - Tea layer was yellow orche and not burnt sienna as written above:)
Putting it all together: (two colors)
The technique sounds all easy but can be quite a challenge when you are on-site and overwhelmed by the gamut of colors and details that mother nature throws at you.
The truth is, no one can paint everything on the spot. A good painting isn't a good photo and how you capture the essence creates the impression that mattered the most. (Paint language)
A few things to note:
Things will change.
You are painting an illusion and it doesn't have to include everything.
A quick thumbnail study is exceptionally useful for a complicated scene. I often make the mistake of painting without preparation, only to regret after I lay down the first wash.
Resolve your value structure before you paint. Changes in light cannot affect your vision if you have this road map. Its also a whole lot easier to focus on other aspects of painting if you have this.
An illustration of how this works. Putting it together for a scene . Note that you want to cover as much as possible with the first lay-in wash.
The watercolor clock as illustrated here and taught by the famous water colorist Joseph Zbukvic. On this clock, he documented the way to assess pigment's consistency versus the result on the various degree of wetness on the paper. His book however is out-of-print but this remained a crucial technique for anyone trying to paint on-sight.