us, though not an equally forcible statement of natural
fact. But if you take away the colours unequally, and leave some tints
nearly as deep as they are in Nature, while others are much subdued, you
have no longer a true statement. You cannot say to the observer, "Fancy
all those colours a little deeper, and you will have the actual fact."
However he adds in imagination, or takes away, something is sure to be
still wrong. The picture is out of harmony.

It will happen, however, much more frequently, that you have to darken
the whole system of colours, than to make them paler. You remember, in
your first studies of colour from Nature, you were to leave the passages
of light which were too bright to be imitated, as white paper. But, in
completing the picture, it becomes necessary to put colour into them;
and then the other colours must be made darker, in some fixed relation
to them. If you deepen all proportionately, though the whole scene is
darker than reality, it is only as if you were looking at the reality in
a lower light: but if, while you darken some of the tints, you leave
others undarkened, the picture is out of harmony, and will not give the
impression of truth.

It is not, indeed, possible to deepen _all_ the colours so much as to
relieve the lights in their natural degree; you would merely sink most
of your colours, if you tried to do so, into a broad mass of blackness:
but it is quite possible to lower them harmoniously, and yet more in
some parts of the picture than in others, so as to allow you to show the
light you want in a visible relief. In well-harmonised pictures this is
done by gradually deepening the tone of the picture towards the lighter
parts of it, without materially lowering it in the very dark parts; the
tendency in such pictures being, of course, to include large masses of
middle tints. But the principal point to be observed in doing this, is
to deepen the individual tints without dirtying or obscuring them. It is
easy to lower the tone of the picture by washing it over with grey or
brown; and easy to see the effect of the landscape, when its colours are
thus universally polluted with black, by using the black convex mirror,
one of the most pestilent inventions for falsifying nature and degrading
art which ever was put into an artist's hand.[262] For the thing
required is not to darken pale yellow by mixing grey with it, but to
deepen the pure yellow; not to darken crimson by mixing black w