Vehicles And Varnishes With Which They Are Mixed Many Of These Have

: ON COLOURS AND PIGMENTS GENERALLY.

been blamed, and often with justice, for their injurious effects on

pigments. The reputation of the most permanent colour may be ruined, if

the vehicle, &c., employed with it be untrustworthy. The presence of

lead, for instance, in such materials renders them liable to be

blackened by foul air, and by consequence the pigments used therewith.



Time produces in many cases a mellow and harmonious change in pictures,

but occasionally alterations altogether unfavourable. To ensure the

former and prevent the latter, the attention of the artist in the course

of his colouring should be to the employment of such pigments and

colours as are prone to adapt themselves, in changing, to the intended

key of his colouring, and the right effect of his picture. Thus, if he

design a cool effect, ultramarine has a tendency through time to

predominate and aid the natural key of blue. He will, therefore,

compromise the permanence of this effect, if in such case he employ a

declining or changeable blue, or if he introduce such reds and yellows

as have a tendency to warmth or foxiness, by which the colouring of

many pictures has been destroyed. In a glowing or warm key, the case is

in some measure reversed--not wholly so, for it is observable that those

pictures have best preserved their colouring and harmony in which the

blue has been most lasting, by the pigment counteracting the change of

colour in the vehicle, and that suffusion of dusky yellow which time is

wont to bestow upon pictures even of the best complexion.



Unless introduced and guaranteed by houses of acknowledged reputation,

newly discovered pigments are to be used with caution. Good colours have

ever been prized with so true an estimation of their value, that to

produce such, after so many ages of research is no ordinary

accomplishment. But too many resplendent pigments, fruits of the

fecundity of modern chemistry, have been found deficient. The yellow and

orange chromates of lead, for instance, withstanding as they do the

action of the sunbeam, become by time, foul air, and the influence of

other pigments, inferior to the ochres. So the dazzling scarlet of

iodine and mercury must yield the palm of excellence to the more sober

vermilion, being a chameleon colour, subject to the most sudden and

opposite changes. And the blues of cobalt, as always tending to

greenness and obscurity, cannot rank beside ultramarine.



We are far from asserting, however, that all modern pigments are

inferior, or that pigments should be looked upon with suspicion because

they are modern. Several most valuable colours have lately claimed