Mahogany.
—Burnt umber, burnt sienna and vandyke brown, with the addition of a little crimson lake for over graining, will answer well for mahogany.
Rosewood.
—Vandyke brown, with the addition of a little black, should be used, and rose pink may be added if desired.
CHAPTER XI.
How to Test the Quality of Colours
Although to accurately test the quality of a colour requires somewhat elaborate experiments, both chemical and practical, yet there is no reason why the painter should not determine with a sufficient degree of accuracy for his purpose the quality of the colour he uses. Indeed, if this were done more generally, much of the adulterated trash or “muck,” as it has been called, would be driven from the market, and none would rejoice more at such a result than the colour manufacturers themselves. The writer has no connection with, or interest in, these manufacturers, but it is only fair to assert that they are as desirous that the trade should use pure colours as the painters can possibly be. Even the biggest houses produce cheap grades of colours, and this they do, as a rule, almost under a protest and simply because they are compelled by painters demanding colours for certain low prices, far below that which it would be possible to produce the pure article. Our advice, then, to painters is, make a careful comparison between the pure colour and the one you are using. At the same time, compare the prices and then see which is cheaper to use. If even they come out at the same price, remember that by using a pure colour you will have all the benefit of that purity of tone so necessary for the execution of good work.
The first thing to be done in testing any paint material is to have a standard. There must be no doubt about this. Unless we have in each case something with which to compare the particular sample of colour that is being examined, we shall have no useful information concerning it. Take, therefore, good decorators’ colours of well known make. If necessary purchase small tubes of the best colours, such as are put up for artists. This will be rather a severe trial but still it will afford a standard. Having such samples and going through the tests we are about to describe, the painter can, after some amount of trouble, arrive at results which are almost as accurate as those which could be deduced by a chemist. An expert on this question some years ago summarised the characteristics of colours which should be considered in making the examination, under the following heads:—
1. Purity of the material.
2. Purity of the tone; brilliancy; richness, which indicate the amount of care in selection.
3. Fineness of grinding or preparation; this means the degree of the division of the particles and upon the completeness of such division will depend.
4. Its spreading capacity.
5. Its body. This applies, of course, only to opaque or semi-opaque colours. Body is opacity, and means capacity to conceal the surface to which the paint is applied, and must not be confused with spreading. It is an inherent quality.
6. Its staining power or tinting strength with white or colours.
7. The quality of purity of the tint with white.
8. If a paste colour, the consistency of the paste.
9. Transparency of transparent colours and the quality of the transparency.
10. The permanency of the colour.
It will be observed that all of these tests will not necessarily be applied to every colour. For instance, a transparent colour would be tested for its transparency but clearly not for its body. The one condition is the converse of the other.
We will now consider the above-named qualities separately.