The word Gestalt has its origins in the world of psychology and philosophy. Sometimes it's described as "essence or shape of an entity's complete form." In visual art, the word Gestalt can be used to describe the wholeness or unity of a painting. The Wikipedia encyclopedia uses the phrase "The whole is greater than the sum of its parts" to explain the word Gestalt. Colour harmony is an important element in achieving unity in a painting. One way to obtain a degree of harmony is to allow the under-painting colour to permeate through and around shapes. Some early Canadian impressionist plein-air painters used pine panels that were varnished. The golden wood colour of the panels was sometimes left around brushstrokes giving the paintings a wonderful harmony.
There is no single solution to achieve that wholeness in a painting and the use of colour is just one important element. Each subject and each season has to be dealt with accordingly. I am sending an example of a quick plein-air painting of a summer scene in Gibson's B.C. using a warm red under-painting that permeates throughout the painting giving a form of harmony.
Looking at the big shapes first and dealing with the smaller detail later helps to overcome the urge to pick away at an area and not to see the whole picture. To have one colour dominant also helps to achieve unity.
This letter was originally published on Robert Genn's "The Painter's Keys" web site.