It produces a magnificent effect to place whole figures and groups,
which are in shade, against a light field. The contrary, _i.e._ figures
that are in light against a dark field, cannot be so perfectly
expressed, because every illuminated figure, with or without a side
light, will have some shade. The nearest approach to this is when the
object so treated happen to be very fair, with other objects reflecting
into their shades.
Shade against shade is indefinite. Light and shade against shade
are mediate. Light against shade is perspicuous. Light and shade
against light is mediate. Light against light is indefinite or
indistinct.
_Edward Calvert._