For mixing with oil color paints, chrome is an undesirable pigment, and it is particularly to be avoided when compounding greens from Prussian or Antwerp blues. which latter colors it would eventually destroy. In such an in stance, for common use, the best substitute for the chrome would be bright yellow ochre, or, as it is often labeled, yellow paint. Raw sienna can also be used with the above blue pigments without much detriment to either. Tn any case where a bright mixed green is absolutely neces sary, the lemon chrome can be used in conjunc tion with good ultramarine blue or indigo.
In compounding the secondary color of pur ple from blues and reds, there is less danger of trouble arising. For oil painting, the best and purest are obtained by mixing ultramarine with madder lake (which is a beautiful crimson and transparent permanent pigment), while lakes derived from cochineal are unstable, or ultra marine and vermilion will answer. Prussian blue and vermilion give very deep purple, which may be lighted up with white. For common purposes, the cheap purple brown is most use ful, if required full in strength; but if lighter and pure tints are wanted in oil or distemper, ultramarine blue and vermilion, or, for cheap ness, Venetian red, is necessary. Prussian blue in water would not suit so well, but indigo could be used if cost is not a consideration.
The remaining secondary, orange, is not a color very much called for. In orange chrome or orange red we have a bright opaque pigment, but otherwise, like all the chromes, not a com mendable article. Burnt sienna is a very oppo site pigment in both nature and source. It is semi-transparent, reliable, and permanent, and, when of good quality, is a remarkably strong stainer, being like Prussian blue in this respect. In compounding orange color, the reds and ochers already mentioned are usually bright enough; yellow ocher and Venetian red, or raw and burnt sienna together, give us, with white lead, a good and serviceable variety of perma nent orange and salmon tints.
The compounding of the third division of material colors, the tertiary, from either of the two secondaries, is a subject that need scarcely here be dealt with. The student who works at this subject practically will soon find, from the foregoing and subsequent remarks, those sec ondary pigments of orange and green which produce the tertiary citrine, whether bright or somber, such as occasion requires.
Of the remaining tertiaries, russet and olive, prepared from the secondaries purple and orange, purple and green, respectively, we have a good supply in the form of simple pigments.
Notwithstanding, therefore, the necessity and advantage of the worker being able to obtain any color by the admixture of the three pri maries, it is always most economical to use a simple article of the desired color when it is to be had.
In the actual mixing of paints, it must not be thought that there is any one way that is exactly right while all other methods are exactly wrong. Every painter has his own peculiar way. In nearly all cases, the simplest plan is to use pigments ground in oil instead of dry powders. With a pallet knife, break up the lead rather stiff, adding a little oil. Thin down each paint until it is rather stiffer than the whole will be when ready for actual application; or, if dry pigments be used, add a little oil, and thor oughly mix. The lead, zinc, or other base being ready, add some pigment, and stir well. If sev eral pigments are required to produce the tint, be sure to add only one at a time, and take great care that each is thoroughly mixed before the next one is added. As a further precaution, it is well not to add the pigment all at once, but to do so a little at a time. When it is certain that a thorough admixture has been effected, the next pigment may be added a little at a time. It is well to remember that some pigments, such as Prussian blue, are very strong, and the addi tion of too much will spoil the job. It is easy to add a little more, while it is impossible to take any out. A little precaution in this respect will save much trouble; and although it takes longer to mix a batch of paint, it is much the safer plan. Of course, a practical man who is used to frequently mixing paints can add the necessary. amount of colors without taking these precautions.
Having mixed the paint, add as much driers as may be necessary, taking care not to use too much. Then the paint should be strained through a fine wire strainer. It is well to mix up enough of the paint in one batch to do the whole of the job in hand, so that there may be no trouble or waste of time in matching tints. Paint mixed in cold weather is very likely to give unsatisfactory results, because the oil will stiffen and be more difficult to form into a per feet admixture. To remedy this, a gallon or so of the oil should be heated, and this poured in will warm up the paint, and prevent it pulling when applied, and so avoid the unnecessary force required to draw the brush along.