Changing the background color dramatically changes color. Color is always relative. It is totally dependent upon the background and surrounding colors. In the below example, both squares of orange seem different, but they are the same. Only different is the background color...
The value (light or dark) of the background also affects color.
In developing a painting, I believe equal amounts of time, should be devoted on objects in the foreground, and the elements of the background. There should be an equal balance between the two.There shouldn't be any significant white remaining on canvas or paper, before dedicating working on a specific objects or areas. Never development a painting with a single entity, but develop as whole thing.
Below is a wonderful example of creating a painting with washes of color in the background. Then preceding painting in layers
As the painting grows, darker values are added and more detail.
As the painting continues, both the foreground and background are developed.
The painting has been created and developed in unison.
