But there is an even more important aspect:
Lighting SynchronizationArtists rarely work under ideal lighting conditions, such as a consistently overcast day when painting en plein air, when the paint and the subject are illuminated almost identically. Far more often, they work under conditions in which the lighting of the working area and the subject differs significantly.
Suppose the artist is painting a still life. The artist works near the studio window, while the arrangement is positioned a little farther away. As is well known, illumination decreases not simply with distance, but with the square of the distance. This means that if you move twice as far away from the light source, the illumination decreases fourfold. If you move three times as far away, it decreases ninefold. Therefore, even a small difference in distance from the light source is very significant, although we do not always notice it.
More light falls on the artist’s working area. When the artist directly compares the color of the paint with the color of the subject, the paint appears lighter. The artist will be
forced to darken all the paints so that they match in value. As a result, all the paints in the picture will be darker than necessary. If the finished work is brought up to the subject, the difference will become obvious: the painting will look too dark.
Conversely, if the arrangement is illuminated more strongly than the artist’s working area, for example by a bright lamp, the paints will appear darker during comparison. The artist will automatically lighten them, and the resulting work will be too light and chalky.
The solution to this problem is to control the illumination of the paint sample itself. Since we cannot always change the lighting of the still life, we can change the angle of the plane holding the paint. This is how the
lighting adjustment of the sample is carried out.
It works just as it does with a sheet of paper: turn it toward the window, and it becomes dazzlingly white; turn it away into the shade, and it becomes gray.
This relationship had been noticed before. John Ruskin advised changing the tilt of a card relative to the light and placing the drawing under the same lighting, while John Collier warned that the color of the paint on a palette knife changes when the knife is turned toward the light. However, they did not propose a systematic way to control this difference. More details can be found
here and
here.By controlling the angle of the plane holding the paint sample, we can artificially “add” or “reduce” the light on the paint, thereby synchronizing its illumination with that of the subject.
This adjustment has a fundamental effect on the final result of the painting. A simple inverse relationship is at work here:
If we turn the plane holding the paint sample toward the light, the paint on it becomes brighter. To obtain a visual match with the subject through direct comparison, we will have to mix a darker paint so that it matches the subject’s color. As a result, when working with the plane adjusted in this way, the entire painting will be shifted toward darker values.
If we turn the plane away from the light, the paint on it becomes darker. To match the subject, we will have to mix lighter paints. With this adjustment, the entire painting will be lighter.
In short:
More light on the sample means a darker painting.Less light on the sample means a lighter painting.By understanding this principle, the artist gains a powerful means of control. Simply by changing the angle of the plane holding the sample, it is possible to consciously regulate the overall tonality of the future work or its individual areas and compensate for differences in lighting.
It was this simple but important condition, the adjustment of the lighting of the comparison plane, that remained unrecognized by artists for a long time and effectively hindered the spread of the direct color comparison method in painting.
Such attempts invariably encountered a fundamental problem: a mismatch between the illumination of the paints and the subject. Without synchronizing them, the painting turned out either very dark or very light, and direct comparisons lost their meaning.