Blog

Good plein air paintings have multiple components: strong composition, value range, accurate color relationships and edges (where one passage connects to another). After defining the composition and value range of the scene, the next issues facing the artist are color themes and color temperature.  Understanding color temperature is an important step in building both color harmony and credible form in a strong painting.  It is possible to show form with just a value description but vibrant work takes advantage of contrasting warm and cool passages as well as accurate values. 

When working outside, one of the first steps is to decide if the light source is warm or cool. During the summer months, light is generally warm, the light has a strong cast to the yellow or red. During the winter, light is saturated with ultraviolet rays which shifts the light color to the blues and purples. One simple way to see this color cast is to put a couple of white canvas panels in the sunlight. Place one panel horizontally and two others vertically  so they cast a shadow on the horizontal panel.  Step back a bit and look at the color of both the light and shadow on the  horizontal and vertical panels. If the horizontal panel has a yellow to reddish cast, the overall light temperature is warm and the shadows will be predominately  of cooler colors - blues, blue greens maybe some purples.  If  the horizontal panel looks more blue, the light has a decidedly cool cast  and the shadows will have comparatively warm colors. It's possible to have warm or cool light colors any time of the year but generally the warmer months have warm colors and the colder months have cooler colors.                                                               

White panels in sunlight

White painting panels in the sun with shadows. Notice the color of the panel in the light is a bit yellow and the vertical panel is more blue.	All the swatches on the panels are the same mixture of Cadmium Yellow Deep with a bit of white. Notice the value range and color change on the vertical and shadow panels.

Now comes the hard part. While there are warm and cool colors, color temperature of paint passages is dependent on the relationship of one color juxtaposed to another as well as the color of the light source. There are no hard and fast cool or warm formulas to be just scrubbed on the canvas. Articulating these relationships are dependent on two things; a grounded understanding of color theory and very keen observation.  Strong paintings have an overall color theme that artists chose when beginning the painting, as well as passages that rely on the interplay of warm and cool colors.

Within a painting, it  is possible to have one passage where a color is perceived as warm, but in another passage the same mixture will appear cool because of the relationship of the paint passage next to it. Often this happens in tints or shades of a color mixture but these subtle effects can help build a very strong painting.

A painter friend sometimes uses a fairly vibrant palette when painting his landscapes.  When finished however, the painting has  depth and form and a strong sense presence,  all the while employing colors that are a bit more saturated that those actually in the landscape.  To achieve this, he carefully maintains the relationship of the light source, color temperature and value as well as utilizing warm to cool passages in the painting to describe form.  If you compared his painting to a black and white photograph of the scene, you would see similar value relationships.

It's also possible to engage warm and cool relationships in place of a series of value changes. Too many value changes in a small area creates confusion; a color temperature change can do the work of one or two value step changes.

Sargent used this technique often in his landscapes and portraits. Known for his conservation of values (using a minimal  range of values to express form in a painting), Sargent often employed warm and cool passages in place of  modeling.  Sargent's portrait of Lady Agnew*, c.1892-93, in the

National Gallery of Scotland,  is one of his most recognizable pieces and often reproduced in books. Look a the paint passages

on the subject's face and you will see an excellent example of  warm and cool relationships creating form without a value change. The subject's dress contrasts with the warm colors of her face, arms and chair, creating a vibrant and masterfully painted portrait.

John Singer Sargent Lady Agnew*

The warm cool passages on the left side of her face show how a temperature change will show form. The cool tones of her dress contrast with the warm tones on the chair and her face and arms.

Understanding the cumulative effects of warm to cool and

cool to warm relationships is beyond this short piece but

there are some good texts that will can help the artist understand this very complex subject.

For a better understanding of color relationships including warm and cool, read  Interaction of Color, by Josef Abers.  While most of his color examples are simple squares or rectangles, the effects are stunning and directly applicable to realist painters. If possible, find a library or museum that owns the original silk screen folios published in 1963 that preceded the hard-bound book.  You may be required to have a museum curator or librarian stay with you while looking at them, but be ready to see some fantastic of examples of  color including many examples exploring the effects of  warm and cool color.

Emile Gruppe's book,  Gruppe on Color, by Watson Guptill  which is now out of print but available second-hand through booksellers is another excellent  text on using color for the plein air painter. There is solid information about color harmonies, palettes  and dealing with warm cool effects.

Understanding light temperature and color relationships are key elements to producing successful work.

Keep exploring and keep painting!

* Lady Agnew by John Singer Sargent; collection of the  National Gallery of Scotland;
image courtesy Wikipedia.