Tuscan Red in Oil. - These reds are a somewhat uncertain material so far as a standard for them is concerned. The color sold under the brand English Tuscan red is not up to some of the proprietary brands made by color makers in the United States, and some of the reds offered by British manufacturers as Tuscan are simply maroon lakes of uncertain origin very much reduced. Up to about the year 1887 the dry color sold as Tuscan red was made by American color makers by precipitating upon a base of about equal parts pure Indian red and English cliffstone Paris white a certain quantity of the mother liquor of rose pink made from Brazil wood, which made a rich color, but a pigment not very strong in hiding power nor very permanent. About that time the general business manager of a prominent paint firm, now long deceased, copyrighted a brand of color under the title "new Tuscan red" that was made in their own color making establishment, and the formula was quite secret for many years. This Tuscan red, though not of great hiding power, is quite rich in tone and very permanent, standing high degrees of heat and exposure to light to a remarkable degree. It was made in three shades, but only the medium shade had a remarkable sale for a long time, though the other two shades also sold well. The base of this red is also chemically pure Indian red mixed in water, to which is added about its own weight of calcined sulphate of lime, also hydrated or wet up with water, both of these run into a striking tub and precipitated upon this base is a certain portion of alizarine red paste or mother liquor. When the mixture is effected the color is washed repeatedly, the precipitate filtered, dried and powdered.
Tuscan red so made, mixed with raw linseed oil, requires 72 to 73 pounds dry pigment to 27 or 28 pounds oil for 100 pounds of paste in oil, holding well in suspension in the containers. A Tuscan red of similar permanency and richness can be made by mixing and grinding 45 pounds dark Indian red, 10 pounds of alizarine red lake and 45 pounds gypsum in 30 pounds raw or refined linseed oil, yielding 128 pounds of paste, allowing for waste. Or still better to save expense in grinding, grind the alizarine red lake separately in its own weight of linseed oil impalpably fine, mix 15 pounds of the resulting semi-paste with 36 pounds each dry Indian red dark and gypsum and 15 pounds raw linseed oil, and the result will be 100 pounds net of Tuscan red paste. Lighter or deeper shades can be produced on same formula by simply using light or extra dark Indian red in place of the dark shade.
A cheap grade of Tuscan red can be made by mixing Indian red and gypsum in convenient proportions, adding sufficient of a carmine substitute pigment otherwise known as scarlet lake or azo-scarlet. While this color is neither permanent on exposure nor heat resisting, it is as good as many consumers desire to have it. By mixing 30 pounds Indian red, light or medium, 40 pounds gypsum, 10 pounds of azo-scarlet lake G, with 22 to 23 pounds of boiled linseed oil and grinding same fine, 100 pounds of a fairly rich red of the Tuscan red type will be the result.
As we remarked at the beginning of the paragraph on Tuscan red, there is no accepted standard for this color, and all that is known about it is that it should be rich permanent red, such as cannot be obtained from even the richest red oxide of iron. Of late some grinders have made their grindings of Tuscan red by mixing in some instances Indian red, in others deep red oxide of iron or Venetian red with some of the so-called body toners of the para nitraniline or beta naphthaline group, selecting such as are least apt to bleed out. Because of this practice no two grinders are producing shades of Tuscan red that are precisely similar, unless they are given samples to match. Pompeiian red in oil, if called for, can be filled out of a grinding made from Persian Gulf red, while Windsor and Victoria reds are simply Venetian reds low in cost.
Before closing the chapter on oxide of iron reds it will be interesting to mention the Tuscan red body color used by the Pennsylvania Railroad for many years on their passenger car equipment. Here is where the late Dr. Dudley and his assistant, Mr. E. N. Pease, broke with the established custom of having the pigment ground in coach japan, falling back on a practice in vogue before the grinding of colors in japan was thought of. The idea was to grind the dry pigment, that was to be composed of oxide of iron and a fairly permanent lake in a vehicle that would not be apt to cause livering in the paste form, as well as to enable the chemists to more accurately determine the constituents of the material, especially the vehicle, than would be possible if the pigment was ground in japan. It was to do away with the overheating in milling and enable the management of the shops to introduce a uniform rule of thinning the paste color for application. The specifications that were issued over twenty years ago and have, with very trifling modifications, been in force ever since, are in substance as follows: - P. R. R. standard car body color Tuscan red is to consist of 75 per cent of pigment and 25 per cent of vehicle by weight. The pigment desired consists of 80 per cent by weight of sesquioxide of iron, not less than 2 per cent nor more than 5 per cent carbonate of lime, balance to be inorganic coloring matter of a character approved by the testing laboratories of the company at Altoona, Pa.; the vehicle to consist of 36 per cent of well-settled pure raw linseed oil and 64 per cent of pure spirits of turpentine by weight. This was followed by the usual caution about fineness of grinding, matching of the shade to the dry standard furnished and the deviation allowed without rejecting the shipments, which practically bars out such as are deficient in the percentage of oxide of iron, contain less than 8 per cent or more than 10 per cent of raw linseed oil in the paste, any oil other than raw linseed oil or any that contains, in the pigment, coloring matter of organic origin or such that has not been approved. For several years past permission has been given manufacturers to cut down the percentage of inorganic coloring matter or to omit it entirely, providing they can furnish the standard shade without such addition, which, however, will be found an impossible task, as the oxide of iron of the maroon shade required, with the brilliancy or richness of tone needed, has yet to be discovered. While at first and for some years alizarine red lake was approved as coloring matter in preference to all others, it would appear that of late coloring matter of the paranitran-iline, the orthoanisidine or toluidine groups of coal-tar derivatives are accepted, and as these so-called toners are far stronger than the alizarine reds it enables color grinders to conform to the specifications as to percentages of pigment and vehicle with far less trouble than had been the case when using alizarine red, which really required excessive portions of vehicle. The shops are given instructions as to how the paste color is to be thinned for use with certain portions of coach japan and spirits of turpentine and the addition of a small portion of varnish for finishing coats. The principal object of this method is to obtain more durability and wear because of the better elasticity and uniformity of the paste so ground as against the same color ground in japan, the theory being that the heating of the material in the milling is not conducive to good results. But while this method of grinding a color of the composition of the P. R. R. Tuscan red appears to work well, it has been found impractical in the case of another railway company that has attempted to introduce it into their Pullman shade of car body color because of the great portion of vehicle required. It was found on thinning the color so ground that an excessive quantity of japan was required to make the color dry within reasonable time, and that this large portion of japan impaired the hiding power of the color. Furthermore, the master car painters found that they were unable to get out the cars from the shops on schedule time, thus causing the motive power department to abandon the practice and returning to the use of color ground in japan.