Lighting, when used effectively, can create emotion and depth in a painting.
At the most fundamental level, light is crucial to a painting. Artists can use it in a classic lighting scheme, helping them define three dimensional shapes, or make it a focal point for the piece, drawing stark images with highlights and shadow. In spite of its importance light can be hard for some artists to capture. When using a versatile and color-oriented medium like acrylics, the best way to paint light is by observing the way it interacts with the world.
Light Direction and Shadows
Shadows define shapes, while light creates shadows. When developing the composition for a painting it is important to decide early on the source, direction and intensity of the light, which will dictate the location and depth of the shadows. A painting can have multiple light sources but the lighting should remain consistent. Light that interacts with one object a certain way should also strike nearby objects similarly. Keeping consistent will tie objects together.
Color
Light has color and is not white, while the shadows are not entirely black. Look at the color of the light being cast and picture how it affects the surfaces it strikes; most of the time they will take on hints of that color to varying degrees. A stone wall will look different in the orange light of a setting summer sun than in the cool light of a noontime sun in winter. You can mix and blend acrylic paints in many different ways to create subtle variations of color as the lighter tones of the highlights move through the mid-tones into the dark hues of the shadows. Avoid using absolute black for shadows, as it tends to be flat and dull.
Detail
Light carries information and detail back to the eye. Too much light and the details are washed out; too little light and the detail sinks into shadow. Better lit portions should have well defined detail while darker portions are simplified. The amount of detail that is lost to the extreme highlights and shadows depends on the strength of the light source. Detail loss is a loss of color variations as well as shape. The optimal area for detail is in the mid-tones. With acrylics, work from the bottom up, laying down the broad simple details of the darks and building up the fine detail of the brighter hues.
Scumble
A method of acrylic glazing is called scumble. Glazing is when the artist thins a color with water until it is nearly transparent. He then paints this over a lighter color to create a soft, delicate blending. Scumble is using that glaze over a darker color instead. Scumble washes out the darker color and creates a flatter look. This is a common method to create hazy light as well as distinct light beams contrasted against a dark background.
