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Taking the Temperature


 by David Hardy

The first step toward understanding color temperature is becoming a keen observer of light.

In nature, color temperature is all around; artists just need to look for it. By identifying color temperature, they can describe their world more effectively. The Venetians recognized this during the Renaissance, an awareness their art demonstrates. And in Antwerp as well, certainly Peter Paul Rubens possessed a thorough knowledge of color temperature, at least in terms of cool light. Yet today, it is easy to find experienced artists who are completely unaware of the concept but still produce quality artwork. So what is the importance of color temperature and why bother trying to recognize and use it? Because with an understanding of temperature, artists can enrich a painting’s color, increasing its vitality and effectiveness without garish results.


Color identity exists in several incarnations. Hue refers to the color family: red, green, or purple, for example. Chroma differentiates intensity, as between the brilliance of cadmium red light, the quieter shade of burnt sienna, and to a greater extreme, the relative somberness of a brown, such as burnt umber. Value identifies the lightness or darkness of a color in relation to black and white. Color temperature describes how colors relate to one another and to the color-temperature extremes of blue (which is the coolest) and red-orange (which is the warmest).

Some artists employ what they call a warm or cool color to describe light and its effect in a picture. Warm and cool are terms of comparison, even opposition. A single color has no temperature. So, while blue is thought of as a cool color and red-orange warm, they must be considered in context with other colors. To refer to warm or cool is automatically to compare at least two colors. You cannot have one without another.


Warm light can be observed easily by looking at the sun shining on a wall or sidewalk. One of the best times to recognize warm light is late afternoon on a sunny day, when the shadows glow with an inviting shade of grayed blue-violet and the lights are steeped with soft, creamy yellow-orange. Just before sunset, light takes on a saturation of intense orange. Indoors, firelight, candlelight, and incandescent light cast warm light, whereas cool light emits from fluorescent sources. Cool light occurs outdoors on overcast days, and it is cool light that streams through north-facing windows.

Occasionally, art instructors remark that warm light shining on a subject produces cool shadows, and with cool light, warm shadows result. But be forewarned: Nature is more complex. Artists cannot capture the true feeling of color in nature just by creating opposite temperatures between light and shadow. They must become keen observers of light in all its magnificence, from the softest visual whispers to the blinding intensity of the sun.


Color is least distorted where light is strong. (The sole exception is glare, found with exceedingly bright light, such as midday sunshine.) As light recedes, surfaces grow darker and color becomes softer, more muted. For example, imagine yourself moving from a bright sunny yard into the gentler light of a dark room that has a few beams of weak sunlight falling onto the floor through small cracks and holes in the doorway. If there were a yellow ball in the strong sunlight of the yard and an identical ball on the floor of the room under a weak streak of sunlight, the ball in the yard would seem brighter. Strong light creates intense color: weak light, darker and duller color. Where there is less warm light, there is less warmth. Therefore, where surfaces are darker and duller, they are also cooler. The sunlight on the yellow ball in the yard would appear lighter, brighter, and warmer: the weak, warm light on the yellow ball in the room would be darker, duller, and cooler.

In the diffusion shadow edge (the fuzzy area where shadow and light come together), this process screeches to a halt. Here, the color temperature seems to reverse itself: The diffusion shadow edge is the same temperature as the light source. If the light is warm, the shadow’s diffusion edge is warm. The yellow balls would have a diffusion shadow edge of muted orange.

Temperature shifts again at the lightest part of the shadow. This area is darker, duller, and cooler than the diffusion shadow edge. Do not march through all your shadows with the same cool, simply making it darker in spots. As the shadows progress into greater darkness and dullness (as they are increasingly distanced from the light source), the darker, more neutral colors of the shadow become warmer, with the darkest parts of a cool shadow the warmest.

Not surprisingly, when describing cool light, the dynamics of warm light are reversed. Where darker warm light is a cool temperature, darker cool light is a warm temperature; where warm light is warm in temperature, cool light is cool in temperature at the diffusion shadow edge. Only the strongest light is unchanged.


The alternation of color temperature has three dynamic parts: the strongly lit parent (the local color) and its two bordering areas (which act as warm and cool color temperatures). For example, if yellow is the parent color, then yellow-green serves as the cool temperature and yellow-orange as the warm. As these colors grow darker and duller, the yellow-green becomes more olive and the yellow-orange becomes a slightly orangish mustard or, darker still, rust or even nut-brown. Keep in mind that all these colors mix in our eyes and mind to create the illusion of a yellow object seen in either warm or cool light, depending upon the sequence.

A few colors present problems in terms of identifying color temperature. How can an artist mix a color that is cooler than blue to use with blue?

What about a warmer warm than red-orange? First, there is no color that is cooler than blue. To establish a sense of warm and cool for blue, bring in its tertiary colors: blue-green and blue-purple. Blue-green is not cooler than blue but is cooler than blue-purple. Yellow is cooler than red, so the yellow in blue-green, compared with the red in blue-purple, makes the blue-green seem cool next to the warmth of blue-purple.

Likewise, there is no warm that is warmer than red-orange. To fill the gap, substitute a red-orange that has been darkened and dulled with green. Contrast this red-orange warmth against the coolness of a red-purple that has also been darkened and dulled . Orange dulled and darkened with either green or blue also can be used as a cool temperature to contrast against the warmth of dulled red-orange.

There is no way to create a darker, duller companion for yellow-green or green by using yellow, so move on to a darker warm: red. Adding red to yellow-green or green produces an olive or even bronze green that can serve as the warm. Mix in the direction of blue-green for the cool contrast to this warmth.

Trying to perceive color temperature can prove frustrating. Many students have claimed, “I just can’t see it.” Usually, this is because they look for color temperature relationships by squinting at the spot they are trying to identify. That may be the proper way to confirm the lightness or darkness of a tonal value, but it is exactly the wrong approach to identifying color temperature. Instead, squint to determine how light or dark a color area is and then, while keeping the value structure in mind, look directly at the same area with your eyes wide open. Next, force yourself to look through it, as though focusing three feet farther on. Or, if you prefer, look at the area with your eyes crossed. Either way, your color response will become noticeably more vivid.


Highlights occur on any surface that is smooth enough to reflect the light source. All highlights have two parts: the stronger light that forms its core and the perimeter (the fuzzy outer edge). The highlight core is always the opposite temperature from the highlight perimeter, and the core’s color temperature depends on the strength or weakness of the light source. Therefore, in the warmth of strong sunlight, the core of the highlight is cool and the perimeter is warm; in the weaker light of candles or firelight, the core of the highlight is warm and the perimeter is cool. Most cool light in nature is relatively weak, resulting in a cool highlight core and a warm highlight perimeter. Artificial lights can be a different story: Blue stage lights provide a warm core and a cool perimeter.

Since we normally encounter strong warm light (such as sunlight and incandescent light) or weak cool light (such as skylight), it is easy to understand why inexperienced artists use white to describe any and all highlights. At first glance they think they see white because the core of such highlights are very light and cool, but closer inspection reveals a light, cool tint of color.

When sunshine is at its greatest strength during midday, glare invades warm lighting. Glare occurs as strong light attempts to create a reflection of itself. Only a small proportion of the highlight perimeter is visible, and its chroma is less than the strong light surrounding it. Because of this, noonday sun looks washed out where it is lightest. Stronger color takes over as we ease into the lighter middle tones.

Reflected images (as on water, glass, or metal) and reflected light (which can bounce off another surface into a shadow) have one thing in common: The color of what is reflected -which is to say the color of the surface from which reflected light has bounced – shifts dramatically into greater warmth. Blue sky, when reflected on water, becomes blue-purple. When a yellow wall reflects light into a shadow, its reflection is yellow-orange or even orange. And the weaker parts of the reflected light are darker, duller, and noticeably warmer still before fusing into the rest of the shadow.

If your goal is to create convincing realism in your work, color temperature enables you to do so with greater effectiveness. Guard against feeling overwhelmed by the many technical configurations. Simply allow warm light and cool light to enter your visual vocabulary. Think of understanding color temperature as a gateway to growing satisfaction as an artist. Your art deserves good color, so look around and let nature guide you.


The founder and director of the Atelier School of Classical Realism in Oakland, California, David Hardy studied at the American Academy of Art in Chicago and the Art Students League of New York in Manhattan. He has shown at John Pence Gallery in San Francisco and is writing a book titled Putting the Real Into Realism, from which he excerpted and adapted this article.