To test patent driers, mix it with raw linseed oil, in the proportion of one to three, and apply to glass. If still tacky at the end of 24 hours, the driers may be looked upon as being of inferior quality.
Varnish brushes are best kept, when not in use, by being suspended in the same kind of varnish in which they are ordinary used.
For thinning gold size, use a little boiled oil, not turpentine.
The practical painter should have an “educated” nose—that is, one that can at once detect adulteration in oil and turpentine.
To mix varnishes is sometimes necessary, when the particular kind required is not at hand. But it is always a bad plan, and is never desirable. When it must be done, do not use the varnish for a few days.