Chrome Green.
—This colour is often made by the addition of a base such as barytes, but the presence of this material is not at all necessary, although the presence of the earth for some reason assists in producing the mixture of Prussian blue and chrome yellow which is used to produce chrome green. A number of different shades of chrome green are sold, usually designated pale, mid (middle or medium) and deep. The tinting strength should be tested by mixing one part of green to, say, a hundred parts of white lead or zinc, as explained elsewhere, or twenty-five parts of lead may be used to one part of green. If it is desired to find out the relative strength for tinting purposes of the green, it can be done very simply in the following manner, but the painter must have a pair of apothecaries’ scales, in order to weigh the different quantities. Take first the same quantity of the green which is being tested as that of the standard. If the colour is not so deep add more green each time, and more and more until the two samples are exactly the same tint. By comparing the weights the experimenter will have accurately the relative value of the two greens for colouring purposes. The test for body of the green is performed in almost exactly the same way as that already described for white lead. Prime a board thoroughly so that there may be no absorption, paint across the centre of it a stripe of white and by its side a stripe of black. When this is thoroughly dry take the two greens; that is, the standard and the one being tested. Then mix both with exactly the same amount of oil and turpentine. Take a clean brush for each and paint over the black and white stripes. The one which has the greatest body will, of course, hide the stripes better than the other one. The experiment is simple, and is very useful as a body tint.