Tone implies a degree of transparency, which in Oil colours is attainable with great facility, by a process termed glazing; viz. passing a transparent colour over a previously prepared tint. There are also some other practical methods of producing it, which are more advisable in certain cases, but which need not be further noticed here. In Water colours, the greater number of pigments used are transparent, and the legitimate method of using them proceeds upon the principle of working entirely in transparent media; which has, at all times, excited great hopes with regard to that branch of Art, as affording a better means than Oil colours (in which the light tints are all composed with opaque white) of producing the brilliancy and truth of Nature, in combination with the transparency (tone) which is required in a work of Art. And it is to be regretted, that in some few, and those popular instances, this advantage arising out of the legitimate use of Water colours, should have been thrown away, without obtaining any equivalent, other than that of hiding or correcting blunders; and that attempts should have been made, by the use of opaque body colours, and a similar method of working, to imitate the effect of Oil painting. The progress of the true art of Water-colour drawing, must necessarily receive a check from the adoption of such a practice, which will doubtless be sanctioned by the idle or the hurried; and attempts to carry out the original prospects and genuine advantages of the transparent medium, will probably become rare, if they should not cease entirely.
It is true that opaque Water-colours are supposed to have an advantage over Oil-colours, in light and brilliant parts, in consequence of the tendency of the Oil (the vehicle, as it is technically termed) to come to the surface, and thus to give a tinge to, or obscure, the purer tints of skies and distant brilliant objects. On this account, they are said to be used by Turner in these parts, when he desires to attain great clearness and purity of colour. But, however, the union of Water-colours with Oil may be advantageous for these purposes, and thus Opaque Water-colours may receive a partial sanction; it cannot be denied that, in the instances previously alluded to, in which the Opaque Water-colours are used for no other purpose than the facility of recovering half-tints that had been too much obscured, the only advantage of Water-colours is abandoned, without obtaining the equivalent of richness, arising from texture in Oil; and the purity of the one art is lost, without attaining the force of the other. A crumbly, bungling appearance is produced, and for no reason, as the practice can never be successfully employed in the parts or objects, in which the use of semi-transparent colours is so invaluable in Oil. And in fact, Opacity, the reverse of what is desired, Tone, is produced by the very same means in Water-colours, by which transparency is attained in Oil.
Breadth of Tone is obtained by a process termed breaking the colours, which is the same with the method of incorporating lights with each other, described in the Sketcher's Manual; viz. graduating each tint into those adjacent, by which means a certain degree of affinity is diffused throughout the whole picture, and Harmony, or Breadth of Tone, is produced. The same results are effected, by a process perhaps abused in the present day, termed Glazing, which consists in passing some transparent pigment of the tone desired, over the whole picture, and thus breaking all the tints in the work with the same colour which produces the affinity required.
CHAPTER II.
RULES FOR PRODUCING PICTURES IN COLOUR.
Although Harmony or Pictorial Colouring does not depend upon any particular quantities or arrangement of particular tints, as the slightest consideration of the infinite variety of Pictures that have been produced will prove; certain quantities and arrangements of certain colours, have been found to effect it.
These discoveries have been made from time to time, and have each been adopted as principles by different artists; and though admitting of considerable variation in details, their effects have been so evidently distinguished by the public as uniform in general aspect, that they have been ranged in classes or schools, to one of which any individual work is instantly referred, by those who have even a slight acquaintance with the Art.
By writers upon Art it has been very generally contended, that there must be a balance of warm and cold colours. A little consideration will show, that this, as well as all restrictive regulations, such as that blue must not come in the front of the picture, &c. are unfounded, or nearly the whole of the Dutch school of landscape and interiors must be condemned as wanting in Harmony, or bad colourists; for Ruysdael and Hobbima, Teniers and Ostade, seem to have had a horror of warm colours, while, on the other hand, Cuyp and Both seem to have had an equal dread of cool tints. That a balance of warm and cold colour is one principle by which Pictorial Harmony may be obtained, is perfectly true; and that there are various means of balancing them is also true; which affords numerous varieties of style or character of pictures. And that the principle deduced by Sir Joshua Reynolds from the Venetian school, that one-third of the picture should (may) be cool, and the remaining two-thirds warm, is also just; and will be productive of beautiful results. The error consists in making these relative proportions indispensable to Harmony.
This chapter will contain such principles as have been found to ensure Harmony. There may, perhaps, be many others in store for future discovery.