incidental light

the light of the sun or the moon, seen in a place from which they are invisible and one cannot discern the source of the light; a place only partly illuminated by such light; the reflection of such light, and the various material effects derived from it; the penetration of such light into places where it becomes uncertain and obstructed, and is not easily made out, as through a cane brake, in a wood, through half closed shutters, etc., etc., the same light in a place, object, etc., where it does not enter and strike directly, reflected and diffused by some other place or object, etc., where does it strike; in a passageway seen from inside or outside, places where the light mingles, etc., etc., with the shadows, as under a portico, in a high overhanging loggia, among rocks and gullies, in a valley, on hills seen from the shady side so that their crests are gilded; the reflection produced, for example, by a coloured pane of glass on those objects on which the rays passing through that glass are reflected; all those objects, in a word, that by means of various materials and minimal circumstances come to our sight, hearing, etc., in a way that is uncertain, indistinct, imperfect, incomplete, or out of the ordinary.

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Giacomo Leopardi – The Zibaldone