[Footnote 2: See Footnote 3] Since white is not a colour but the
neutral recipient of every colour [Footnote 3: _il bianco non e
colore ma e inpotentia ricettiva d'ogni colore_ (white is not a
colour, but the neutral recipient of every colour). LEON BATT.
ALBERTI "_Della pittura_" libro I, asserts on the contrary: "_Il
bianco e'l nero non sono veri colori, ma sono alteratione delli
altri colori_" (ed. JANITSCHEK, p. 67; Vienna 1877).], when it is
seen in the open air and high up, all its shadows are bluish; and
this is caused, according to the 4th [prop.], which says: the
surface of every opaque body assumes the hue of the surrounding
objects. Now this white [body] being deprived of the light of the
sun by the interposition of some body between the sun and itself,
all that portion of it which is exposed to the sun and atmosphere
assumes the colour of the sun and atmosphere; the side on which the
sun does not fall remains in shadow and assumes the hue of the
atmosphere. And if this white object did not reflect the green of
the fields all the way to the horizon nor get the brightness of the
horizon itself, it would certainly appear simply of the same hue as
the atmosphere.
On gradations in the depth of colours (279. 280).
279.
Since black, when painted next to white, looks no blacker than when
next to black; and white when next to black looks no whiter than
white, as is seen by the images transmitted through a small hole or
by the edges of any opaque screen ...
280.