Zinc White or Zinc Oxide has, in recent years, made great advances in popularity among painters. Compared to white lead, it is as white to yellow. It is indeed beautifully white, very fine, and easily worked. The whiteness is of importance in mixing paints, as the purity of color is retained, while when mixed with lead the yellowish cast to some extent destroys the purity of the original color. The fact that oxide of zinc is non-poisonous is a point in its favor of very considerable importance. It is claimed that painters who take care to wash themselves frequently and to take every precaution, are not likely to contract lead poisoning. As a matter of fact, the best of painters are at times careless, while in the rush of work, it is often impossible to take the precautions required. The most important quality of zinc white is its extreme durability.
Properly mixed it will last, at a moderate estimate, twice as long as lead, especially in large cities where the air is impregnated with sulphur derived from burning coal. Lead, in such circumstances, turns yellow or black and quickly decays, and some places, such as stables, where sulphuretted hydrogen abounds, it is useless to paint with white lead, and if zinc is used these disadvantages are avoided.
Zinc white has a very good body, better, or as good as white lead. If a proper comparison be made, and if both be thinned out to a consistency suitable to be applied by brush, it is true that zinc white will apparently not have so good body as lead, but it will spread much farther. If an exactly equal quantity of lead and zinc are both painted on an exactly equal area, zinc will cover a little better than lead. In this state, however, the consistency of the zinc paint would be rather too thick. It is easily thinned, more so, comparatively, than the lead would be.
A consideration of these facts will show the practical painter that less zinc than lead will be required to perform a good job, and when the durability is also taken into consideration as well as the beauty, it will not take long for him to make up his mind as to the superiority of zinc.
There is one point, however, about its use which must be explained. Zinc white is, when compared with lead, quite light in weight, or, in other words, its volume is much greater than lead. Now, it being an entirely different product, it must not be treated in the same way as lead would be. The painter, perhaps, takes some zinc, mixes it with raw oil, with a liberal amount of patent driers and a more liberal dose of turpentine, and then he grumbles because it does not show up to advantage. What he does is to destroy its inherent good qualities. To repeat then, zinc white must not be treated in the same way as white lead.
The proper way to treat zinc white is to mix it with refined boiled oil, no driers should be used, and only just sufficient turpentine to bring it to the required consistency. Being pale, it does not destroy the whiteness of the zinc, while it certainly aids considerably in drying. In fact, it is the only practical drier for the zinc, far better than patent driers, or any other goods of the kind. It is paler than raw linseed oil, and hence it does not destroy the most delicate tints, however light.