The yellow colors for coach and car work that are listed under the caption of Superfine Coach Colors, as a rule, are not necessarily ground in what is understood as japan, but may be ground in the brown siccative known as color grinders' or coach painters' japan, in gold size, rubbing varnish, finishing varnish or in part oil, turpentine, etc. The meaning of the term "in japan," which is collective for a group or type of colors in paste form is that when reduced to brushing consistency and so applied to the proper surface, they will dry quickly to a more or less "matt" or flat surface that is to be coated with one or more applications of varnish.
There are any number of yellow colors of this type, so far as the vehicle is concerned, and they run with fanciful names from the palest cream yellow tint to the deepest orange. As most of them must be produced to match certain standards adopted by consumers we will confine ourselves to the description of those found in almost every color grinders' list, adding a few formulas for attractive car colors.
French Ochers in Japan. - It is, of course, optional with the color grinder whether he prefers the light citron shade or the dark shade of the J. F. L. E. S. superior quality of French ocher. The vehicle in this brand is usually color grinders' brown japan, that should be tempered with at least 5 per cent of raw linseed oil, and, if the japan is of the very quick type, 10 per cent oil would not be excessive, because ocher is a brittle material at best. We suggest a mixing of sixty-eight pounds of bone dry ocher, thirty-two pounds color grinders' brown japan and three pounds raw linseed oil, to be ground fine on a water-cooled mill, well sharpened, which should result in producing 100 pounds finished color.
Golden Ocher in Japan. - The pale shade of this is a favorite with railroad equipment painters for lettering and ornamenting on cars and engines when gilding, for some reason or another, is not desired. It is made, as a rule, by mixing sixty-two pounds of J. C. L. E. S. ocher, eight pounds medium chrome yellow of pale shade, thirty pounds color grinders' japan and three pounds raw linseed oil, resulting in 100 pounds finished material.
The dark shade, which is more seldom called for, is made by mixing sixty pounds of J. F. L. E. S. ocher, ten pounds orange chrome yellow, light shade, thirty pounds color grinders' japan and three pounds raw linseed oil, producing 100 pounds color, when ground fine.
Imitation of Gold in Japan is usually bought in one-fourth-pound collapsible tubes, but most coach painters mix their own color from flake white, chrome yellow and vermilion red, with perhaps a little ocher thrown in. Mix eighty pounds finest quality dry white lead, eight pounds medium chrome yellow, two ounces toluidine red (fast scarlet toner) with two and one-half pounds gold size japan, seven and one-half pounds pale rubbing varnish, two pounds refined linseed oil and four pounds turpentine and grind fine on water-cooled mill. Produces 100 pounds paste that will answer very well for lettering and striping. If not warm enough in tone, add more red.
Dutch Pink in Japan is not called for very frequently, probably on account of the coach painters' custom of purchasing composite greens and other colors of this type that contain this pigment ready ground. Still it should be on the coach color list, under either this name or as English or Italian pink. But as it should serve as a glaze over greens or olive tones it should be ground in a pale vehicle to impalpable fineness and the pigment selected should not have a base of whiting, but of alumina sulphate. Mix seventy-two pounds dry color with either pale gold size japan to make 103 pounds or a mixture of twenty-six pounds pale rubbing varnish, three pounds raw linseed oil and six pounds turpentine, resulting in 100 pounds finished color in either case when ground on a good water-cooled stone mill.
Chrome Yellow in Japan. - Canary, lemon and primrose yellows are pretty much the same type of chromes, differing slightly only in shade, but more in tone. Canary yellow is cleaner and paler than lemon yellow, while primrose is also cleaner and paler, but more greenish in tone than lemon. The most successful vehicle for use in grinding any chrome yellow has been found by the author to consist of eighty-two parts by weight of pale hard-drying rubbing varnish, six parts well clarified raw linseed oil and twelve parts pure gum spirit of turpentine. In place of the rubbing varnish a pale hard picture varnish of twelve hours drying will also answer. We shall refer to this as yellow thinners. To mix either the color for primrose, lemon or canary yellow use eighty pounds of the dry color and twenty-four pounds yellow thinners to obtain 100 pounds finished color.
Medium Chrome Yellow in Japan requires more vehicle than either light or dark shades, and, while the bulk of this yellow varies somewhat, it is safe to say that seventy pounds dry color mixed with thirty-three pounds yellow thinners will, when carefully ground on suitable soft stone water-cooled mill, render 100 pounds finished product.
Orange Chrome Yellow in Japan, normal or dark, is not quite as dense as the lemon shade and therefore requires more thinners to manipulate in mixer and mill. Seventy-six pounds dry color and twenty-eight pounds yellow thinners will produce 100 pounds finished color.
Cadmium Yellow in Varnish. - This sulphur compound is stable only in its darker shades - that is, the normal or medium and the dark or orange and deep orange, if such is offered. The pale and light shades contain other metals such as tin and zinc and are prone to fade in strong light. Inasmuch as cadmium is high in cost, it will not pay the grinder to experiment a great deal, and he had best confine himself to the two shades M. and D. Cadmium yellow in varnish being used as a finish or glaze color over other yellows, it cannot be ground in japan, but must be mixed with a hard gum pale finishing varnish with enough turpentine to grind well. The vehicle should be an article made from selected XXXX kauri gum with twenty gallons oil to the 100 pounds of gum, thinned with pure gum spirits of turps only. Figure on seventy-six parts of dry cadmium yellow M. or D., twenty-four parts of varnish and five parts turpentine for 100 pounds finished color. This color must not be put up in collapsible tubes or in tin or iron containers, but is usually put up in glass jars, mostly one-pound size, otherwise the color tends to blacken.
Permanent or Zinc Yellow, also sometimes branded Perfect Yellow, is used but little in coach work, due probably to prejudice on account of its zinc constituents. Is used for ornamenting on sleighs and automobiles, however, and is best ground in the yellow thinners above referred to, requiring twenty-six pounds thinners to seventy-eight pounds dry color for 100 pounds finished color. In grinding all these yellows, overheating of mixer and mills must be guarded against and cadmium yellow especially must not be ground in an iron mill, and even a stone mill must not have an iron scraper and steel spatulas must not be used.
Naples Yellow in Japan. - True Naples yellow is rarely looked for and is usually imitated with ninety-five pounds flake white and five pounds golden ocher in japan. However, the true article is still obtainable and the price of the dry material is not extraordinarily high. While it requires more thinners than white lead, it is, if anything, denser. Eighty-six parts of dry pigment and sixteen pounds yellow thinners will make 100 pounds of paste of either shade, A or C, which are the marks for light and dark, as sold in the market.
Sulphur Yellow or Brimstone Yellow in Japan. - These are simply white lead tinted with either lemon chrome yellow or zinc yellow, according to the depth of shade desired. For the light shade two pounds zinc yellow and eighty-seven pounds fine white lead and about twelve or thirteen pounds yellow thinners; for the dark shadow two pounds lemon chrome yellow to eighty-seven pounds white lead and twelve or thirteen pounds yellow thinners will be sufficient for 100 pounds finished color.
Citron or Citrine Yellow in Japan is made from a mixture of eighty-six parts white lead and three parts lemon chrome with a trifle of ultramarine blue or green added to give the greenish cast, grinding in twelve parts yellow thinners to produce 100 parts paste.
Car-Body Yellows in Japan. - These are ground to match the standard specified by the owners, but very seldom consist of straight chrome yellow in japan. The base is almost invariably basic carbonate of lead (white lead) and the coloring matter may be lemon, medium or orange chrome yellow and sometimes French ocher or any admixtures of these. A light car-body yellow much used by certain street railways is made as follows: - Forty-two pounds dry white lead, forty-two pounds dry lemon chrome yellow, mixed with eighteen pounds yellow thinners as noted above. Produces 100 pounds paste color in japan. A medium car-body yellow known to the author is based on this: - Forty pounds white lead, dry, twenty-five pounds J. C. L. E. S. ocher, fifteen pounds medium chrome yellow, mixed with and ground in twenty-two pounds yellow thinners, producing 100 pounds of color of great covering power.
Omnibus Yellow in Japan, made with thirty-five parts white lead, dry, thirty-five parts orange chrome yellow, D., ten parts dark Venetian red, dry, twenty-two parts color grinders' japan, producing 100 pounds of an orange maroon color of very good body.