Blue
This is another of the primary colors and a very essential one, it
being the nearest allied to shade, and although not shade itself, no
shadows can be produced without it. We will find it, therefore,
mingling with all the shades of nature between the lights and shadows.
It would be in vain for us to introduce all our warm colors, if the
cool tints that are produced by blue are wanting; for, without that,
the work will
ppear heavy, as it is the contrast between blue and the
warm colors that produces a balance of color. Blue mixed with yellow
makes a very brilliant green, with gold a duller green, with magenta a
purple. In landscapes it is used in skies and the middle distances, but
not in the foreground, unless mixed with yellow. Blue can be mixed with
rose or magenta for sunset skies. When the horizon is represented a
streak of blue or rose, or of blue and magenta, will give a very
pleasing effect. In portraits if you have a light background, a thin
wash of blue can be used over it. The same can also be used for blue
eyes and for dresses when they are light in the picture, also in all
the half-shadows of the dresses or draperies without regard to what
their other color may be.