Warm and Cool Colours: Using Temperature to Create Depth

Ask most people to name a warm colour and they will say red, orange or yellow. Cool colours bring to mind blue, green and violet. That is a good starting point, but painters use temperature more subtly than that. It is a relative idea, and learning to see it gives your work a sense of light and depth that is hard to achieve any other way.

Temperature is relative

A colour is only warm or cool compared with another. A yellow that leans towards green looks cool beside an orange-yellow. A blue that has a hint of red in it, like ultramarine, feels warmer than a greenish blue such as phthalo. Every hue therefore comes in a warm and a cool version, and good painters keep both on their palette. A typical limited palette might hold a warm and cool yellow, a warm and cool red, and a warm and cool blue.

Why temperature creates depth

In the natural world, distant objects are usually bluer and paler because of the air between you and them. Nearby objects look warmer and more saturated. You can borrow this effect: place cooler, softer colours in the background and warmer, stronger ones in the foreground, and the picture appears to open up. This is sometimes called atmospheric perspective, and it works even in a small sketch.

Temperature and light

Light has its own temperature. Late afternoon sun is warm and golden, while an overcast sky gives cooler, bluer light. A reliable principle is that shadows tend to lean the opposite way to the light. If the light is warm, shadows often look cooler, and if the light is cool, shadows can look warmer. Look at a white cup on a sunlit table: the lit side may be creamy yellow, while the shadow is a soft violet-grey. Painting those shifts is what makes an object feel lit rather than flat.

How to use it in practice

1. Squint at your subject and decide whether the overall light is warm or cool.
2. Choose a dominant temperature for the painting and let a small area of the opposite temperature act as an accent.
3. Paint lit areas in the temperature of the light and shadows in its opposite.
4. Check the foreground and background and push them slightly apart in temperature.

A small touch of cool in a mostly warm picture, such as a blue-grey scarf in an orange-toned portrait, attracts the eye precisely because it differs from its surroundings.

Mixing temperature-shifted neutrals

You do not need a different tube for every shift. Adding a touch of blue to a brown cools it, and adding a touch of orange to a grey warms it. If you want to make neutrals that lean one way or the other, the approach in mixing natural greys gives you complete control over the temperature of your darks and mid-tones.

A quick experiment

Paint three small squares with the same mid-value grey-green. Next to the first, add a warm orange stripe; next to the second, a cool blue stripe; leave the third alone. Notice how the green seems to change in each case, appearing cooler beside orange and warmer beside blue. This effect, known as simultaneous contrast, is the reason that colours must always be judged in context, not alone on the palette.

Frequently asked questions

Is green warm or cool? It depends on the green. A yellow-green feels warmer, while a blue-green feels cooler. Green sits in the middle of the wheel, so it is a good colour for practising relative temperature.

Do I have to keep warm and cool colours separate? No. Most paintings mix both, and the interplay is the point. The aim is control, so the viewer feels the light and space you intend.

Can black and white paintings use temperature? Not in the same sense, but you can tint greys slightly warm or cool, which is a quiet way of adding temperature to an otherwise neutral image.