Painting a stormy sky with its dark, dramatic clouds or the pinks and reds of a sunset is very appealing. A little knowledge about the common cloud forms and their characteristics will help you to capture these scenes and enable you to add credible clouds to any painting.
How are Clouds Formed?
Although it's invisible to the naked eye, the air around us contains water vapor. When air rises, this cools the water vapor, which then forms droplets or, at a high altitude, freezes into ice crystals. This is what we see as clouds. Slow-rising air creates sheets of cloud, while fast-rising air creates cotton-wool lumps of clouds.
How are Clouds Named?
Clouds are classified by how high up in the atmosphere they occur. The long, sheet- or ribbon-like clouds found in rows at low altitudes are stratus clouds. Rows of small, cotton-wool clouds found at similar altitudes are called stratus cumulus. Large, billowing, cotton-wool clouds are cumulus clouds. These can extend to great altitudes; when the top flattens out in an anvil shape it gets called a cumulonimbus cloud (nimbus is a term used to describe a dark, rain-bearing cloud). Cumulonimbus clouds are the ones that generate dramatic thunder storms and hail. The whispy clouds found at very high altitudes are cirrus clouds; these are made from ice crystals.
How do I Paint Stratus Clouds?
You want long, horizontal sweeps across your painting, so use a flat, wide brush. The lines of the cloud should almost be parallel, but paint them freehand, not using a ruler. If they're perfectly parallel they'll look artificial. Remember that perspective applies to clouds too, so they become narrower (smaller) and paler the further away they are.
Suggested colors: A light and a dark blue, such as cerulean and ultramarine, for the sky; yellow ocher and Payne's gray for the 'dirty', rain-loaded bits of the clouds.
How do I Paint Cumulus Clouds?
Think of the strong winds that whip up these clouds, and try to translate this action into brush strokes. Work fast and energetic not slow and painstakingly meticulous. Resist the temptation to make these clouds simply white with dark shadows. Clouds reflect colours and may include reds, mauves, yellows, grays. Concentrate on the shadows, which give the clouds shape.
Suggested colors: alizarin crimson for pink tints; yellow ochre and cadmium orange for golds; Payne's gray or burnt sienna mixed with one of the blues used in the sky, for shadows.
How do I Paint Cirrus Clouds?
These are feathery clouds very high up in the atmosphere, swept along by high winds. Be light-handed to capture their wispiness. If they're pure white, consider lifting off the blue of your sky to reveal a white ground rather than painting with an opaque white, trying to leave parts white, or using masking fluid.
Suggested colors: alizarin crimson for pink tints; yellow ocher and cadmium orange for golds.