_On the Juxtaposition of Coloured Bodies with Black._
(See Plate 9, Page 54.)
53. A black surface being deeper than that which is contiguous to it,
the contrast of tone tends to deepen it still more, while it tends
to lower the tone of the contiguous colour; as on the other hand
white, placed in juxtaposition with it, would heighten it. So much for
contrast of tone.
54. Black surfaces reflect a small quantity of white light (4), and
this falling upon the retina simultaneously with the coloured light of
a contiguous body, it is evident that the black surface must appear
tinted with the complementary of the coloured light; but it will be a
weak tint, since it is displayed upon a ground which has but a feeble
power of reflecting light. So much for the contrast of colour.
55. The lowering of the tone of the colour contiguous to the black
is constantly observed; but a very remarkable fact is the weakening
of the black itself, when the contiguous colour is deep, and of a
nature to give a luminous complementary, as orange, orange-yellow,
greenish-yellow, &c.
_Red and Black._
56. Green (the complementary of Red), when placed by the side of Black,
makes it appear Reddish. The Red looks clearer, partaking less of
Orange.
_Orange and Black._
57. A Blue (the complementary of Orange), when placed by the side of
Black, causes it to appear less brilliant, or somewhat rusty, while
Orange by the side of Black appears more brilliant in colour.
_Greenish-Yellow and Black._
58. Greenish-yellow (the complementary of Violet), when placed by the
side of Black, gives it a Violet tint, whilst the Greenish-yellow
becomes clearer and more Green; but there are some kinds of Yellow
which are weakened by the side of Black.
_Green and Black._
59. Red (the complementary of Green), when placed by the side of Black,
causes the Black to appear more Violet or Reddish; whilst Green by the
side of Black becomes slightly Yellower.
[Illustration: PLATE V.]
_Blue and Black._
60. Orange (the complementary of Blue), when placed by the side of
Black, causes it to appear brighter, while the Blue becomes clearer and
somewhat Greener.
_Indigo and Black._
61. Orange-yellow (the complementary of Indigo), placed by the side
of Black, causes it to look much brighter. The Indigo also appears
brighter.
_Violet and Black._
62. Violet (the complementary of Greenish-yellow), when placed by the
side of Black, lightens it up; whilst the Violet becomes more brilliant
and clear, and somewhat Reddish.