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Light is a form of electromagnetic radiation directly emitted from lumi-
nous sources (sun, lamps, candles), absorbed and reflected by opaque surfaces
and refracted through transparent surfaces. The visual characteristics of sur-
faces are distinguished by their response to light. All surfaces either absorb,
reflect or refract light, or perform these actions jointly, to some degree.
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Some works of art use colour, surface texture and materials with the spe-
cific aim of reflecting a high proportion of the ambient light; this is a charac-
teristic of paintings that employ gold and other precious metals, including
Byzantine painting and mosaic, Romanesque illuminated manuscripts and Ital-
ian panel paintings from the 13
th
to 14
th
centuries. Other works create an illu-
sion of the presence of light within the picture by arranging colours in combi-
nations that reflect the distribution of light and shadow values in nature. Most
Western representational painting from the Renaissance to the present creates
pictorial light by colour juxtapositions. The illusion of pictorial light is created
through the interaction of the painting surface with the light that strikes it (the
‘incident light’).
Tonal modelling is the most commonly used practice to create the illusion
of three-dimensional relief. It depends on gradations of lighter and darker
tones of the same colour, which describe the variations in light intensity over
the surface of a form. In addition to mixing colours to get these variations, to-
nal modelling has also been accomplished by layering translucent colour over
gradated un-derpaintings, and by the juxtaposition of small colour areas to
create optical mixing. Scholars have identified different approaches to tonal
modelling, including the use of pure colour in the shadows mixed with white
to create lighter tones (described by Cennino Cennini and used in Italian paint-
ing, 1290–1450); the use of saturated colour in the mid-tones with light and
dark additives to create chiaroscuro
(described by Leon Battista Alberti and
used in Italian painting from 1440); the use of saturated colour in the high-
lights with gradual darkening to create shadows through tonal underpainting
(used by Leonardo da Vinci in the “Virgin of the Rocks”, 1485; and other
works); and hue-based modelling known as cangianti, in which a lighter hue
such as yellow represents illuminated portions of drapery, while a darker hue
such as violet represents shadowed portions (used by Michelangelo in the lu-
nettes on the vault of the Sistine Chapel, 1508–1512, in Rome).
Colour juxtapositions contribute to the illusion of pictorial light, because
the perceived brightness or an object depends on its relationship to other
brightness values in the total visual field.
Contrasts of light with dark result in
the light looking brighter and the dark, darker. Since saturated colours are per-
ceived as more vivid and brighter than greyed colours, the use of saturated
colours or the juxtaposition of saturated with greyed colours can enhance the
illusion of brightness. Contrasts of complementary colours mutually intensify
the perceived saturation of each colour and, when juxtaposed, may create lu-
minous, scintillating perceptual effects. Pictorial light has a more limited tonal
range than light in most natural conditions; therefore, painters frequently use
bold contrasts to create enhanced perceptual effects. Frequently white as a lo-
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cal colour is toned down so that pure white, juxtaposed with darks, serves to
imitate the intensity of lustres.
The pattern of light and shadow follows optical principles that give infor-
mation about the location and quality of the light. Surfaces close to the source
of light appear to be brighter than those which are remote. Shadows vary in
darkness, shape, colour and clarity of edges according to their distance from
the light, their orientation to the light source and their relation to other reflec-
tive surfaces. The description of pictorial light should take into account the
following elements: the type of light represented, whether natural (daylight),
artificial (lamps, candles, torches), supernatural or a combination; the quality
of light, whether direct and focused or indirect and diffused; the level of illu-
mination; the direction of light, whether frontal, lateral, cross-light, backlight,
overhead or from below; the colour of the light; and the relationship between
the pictorial light and the actual light.
The direction of the light source is indicated by the size, shape and posi-
tion of shadows and highlights. When the light source is high, as at midday,
cast shadows will be short; when the light is low, as at twilight, cast shadows
are long. Cast shadows are projected according to the laws of linear perspec-
tive and are shown as foreshortened if seen at an oblique angle. If the light
source is smaller than the object, the cast shadows will diverge and gradually
lessen in intensity; sources larger than the object cause the cast shadows to
converge to a point and lighten rapidly. Sunlight results in cast shadows that
are parallel because at the great distance of the sun from the earth. The quality
of light is indicated both by colour and design: high or strong contrasts indi-
cate an intense light, while low contrasts indicate a weak light. Crisp edges on
forms and cast shadows indicate a focused light, while soft blurred edges and
penumbra suggest diffused light. Bright light reveals colour at its most satu-
rated; dazzling light makes colour appear washed-out; colours in dim light ap-
pear greyed or pale. Incandescent illumination has a warm, reddish-yellow
colour; daylight and fluorescent light have a cool, bluish tonality. In moderate
conditions, reflected light is particularly evident; the light reflected into shad-
ows makes them appear lighter and more transparent, enabling us to see the
contours, details and colour of the shaded object. Reflected light picks up the
colours of adjacent surfaces and transforms the colour of objects.
The most typical placement of the light in Western European painting is
frontal-lateral from above – at about a 45° angle – which illuminates about
three-quarters of the surface of objects and seems most natural. Frontal light-
ing tends to give bold, direct effects; Edouard Manet used this to great advan-
tage in “Le Déjeuner sur l’herbe” (1863) and the “Bar at the Folies-Bergère”
(1882). Backlighting (also known as contre-jour) creates dramatic effects, as
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in Rembrandt’s “Blinding of Samson” (1638), “Supper at Emmaus” (1628-
1629) and other works from his early years. Lateral lighting produces alternat-
ing zones of light and shadow, which were exploited for spatial effects by
such Baroque landscape artists as Claude Lorrain. Cross-lighting (two or more
sources) was used by Domenichino (e.g. the “Last Communion of St Jerome”,
1614) to mitigate the obscurity of shadows, rendering shadowed forms visible
without disregarding the laws of nature. Light from below was frequently used
by Georges de La Tour, Gerrit van Honthorst and other tenebrist painters for
its eerie, disturbing quality.
Bell J. C. Light // The Dictionary of Art / еd. by J. Turner. Vol. 19: Grove’s Dictionar-
ies Inc., New York, 1996. P. 351–353.
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