TWELFTH ANNUAL YEAR BOOK— PART X 513 



ocher and umber; brown, by the addition of mixtures of black, red, and 

 sometimes yellow. Yellow and cream may be made by the addition of 

 ocher or chrome yellow; frequently for this purpose golden ocher Is used, 

 which is ordinary ocher brightened by the addition of a small amount of 

 chrome yellow. Blue tints may be made by the addition of small amounts 

 of Prussian blue. This is a powerful tinting pigment, and it is seldom 

 that more than 1 per cent is required. With the white paints which con- 

 tain no lead, ultramarine blue may be used instead of Prussian blue; but 

 ultramarine blue should not be used with lead paints. 



Besides the tinted white paints, bright colors are sometimes desired, 

 especially green, for blinds, and reds for the trimmings of houses or for 

 machinery. These paints seldom contain any large amount of the expen- 

 sive lead and zinc white pigments, but consist of comparatively small 

 quantities of coloring matter and large amounts of the cheap white pig- 

 ments. For black paints there is practically only one coloring substance, 

 namely, carbon, which, however, occurs commercially in a number of forms. 

 The color of so-called drop or ivory black is carbon, obtained from charred 

 bone; lampblack is carbon in the form of soot. The latter, although very 

 pure, does not make a satisfactory black alone, the heavier forms of 

 carbon, such as bone black or even ground charcoal, producing a better 

 black. 



In the following table is given the composition of several tinted paints, 

 and also of bright red, bright green, and black. The composition of indi- 

 vidual lots of paint of any of these tints or colors might vary considerably 

 from that given, and the table is only illustrative of the materials from 

 which these different kinds of paints may be made. An estimate of the 

 cost of the raw materials entering into the different formulae is also 

 included. The total cost per gallon does not make any allowance for labor 

 or for containers, but is based solely upon the cost of the raw materials, 

 assuming that white lead and sublimed white lead cost 7 cents a pound, 

 white zinc 8 cents, and the other white pigments, barium sulphate, china- 

 clay, whiting, and asbestine, 1 cent a pound. The price of the coloring 

 material is given separately for each paint. These prices for the raw 

 materials are a fair approximation of the retail price at the present time. 

 In calculating the cost of the paints per gallon it is assumed that the 

 vehicle in all cases is the same as that described heretofore and it is 

 valued at 12 14 cents a pound. An inspection of the table shows that there 

 is comparatively little difference in the cost of the materials entering into 

 these paints, with the exception of black paint, which is considerably 

 cheaper than any of the others. The red paint is colored by an expensive 

 color, para-red, costing 78 cents a pound; the rest of the pigment, how- 

 ever, is cheap, and it will be noticed that the paint weighs only 11.6 pounds 

 per gallon, whereas some of the others weigh much more. 



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