Smith, John: A catalogue raisonné of the works of the most eminent Dutch, Flemish, and French painters: in which is included a short biographical notice of the artists, with a copious description of their principal pictures : a statement of the prices at which such pictures have been sold at public sales on the continent and in England; a reference the the galleries and private collections in which a large portion are at present; and the names of the artists by whom they have been engraved; to which is added, a brief notice of the scholars & imitators of the great masters of the above schools (Part 1) (London: Smith and Son, 1829)

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INTRODUCTION.

persons is, that coldness and crudity pervade the picture,
instead of those sweet and harmonizing tones which the
softening pencil of time produces, by blending the various
tints, and covering, as with a veil, the imperfections of
newness, which, by this imprudent system, are exposed
to view; and a picture of one or two hundred years’ exist-
ence is made to show the freshness of a work of yesterday.
There are some collectors, well known in the circle of
connoisseurs, who cannot endure the sight of the
smallest grain of dirt, or the slightest tinge of yellow
varnish upon a picture ; to remove these, the painting
must undergo an operation by which, even in skilful
hands, it is exposed to injury, and may lose many of its
precious tints, or tender glazings, although the injury
be not perceptible to the unpractised eye. Many hun-
dred pictures have been deteriorated by this barbarous
practice; and many thousands of pounds, in their in-
trinsic value, have been heedlessly sacrificed by the
unwary proprietors.
It is not meant to be said, that “pictures are never to
be cleaned,” for their preservation depends on judicious
cleaning. If they be neglected for many years, and are
exposed to a powerful light, to the heat of the sun, or
to a moist atmosphere, the varnish, which protects
the painting, will decompose, and the colour, thus
unprotected, will perish, unless the old corroded in-
crustation be carefully removed, and fresh varnish
applied.
Accumulated varnish, and with it oftentimes dust
and dirt, particularly in the atmosphere of large cities,
will, in a few years, if not frequently wiped, so obscure
a picture, that its beauties will be concealed; damp