140 PAINT TECHNOLOGY AND TESTS 



" An examination of the combination formula grays by the 

 committee led to the general conclusion that those grays which 

 did not contain a very large percentage of white lead were superior 

 in their maintenance of tone and tint and general condition to 

 any of the other grays upon the fence. However, the presence 

 of umber, ochre, and red oxide in some of the grays which showed 

 to the best advantage may account for their permanence of tone. 

 Some of these grays were the so-called warm grays and were 

 much darker in tone and tint than the ordinary drab which is 

 generally applied. 



" The straight pure Basic Carbonate- White Lead paints were 

 not painted out in grays or yellow, the test upon this material 

 being only in white. 



" On Panels 120 and 126, which represent formulas 6 and 9 

 respectively, the 'grays are in most excellent condition, and it 

 will be found, by reference to formulas 6 and 9, that there is an 

 absence of white lead in their composition. These formulas, 

 however, contained a small percentage of umber and ochre. 

 Formulas 5 and 16 contained over 20% White Lead and the 

 gray of these formulas maintained their blue tone very well. 

 These formulas were tinted solely with lampblack. 



" An inspection of Panel 138, which represents Formula 15, 

 showed good maintenance of color in the gray, and was in much 

 better condition as regards permanence of color than the other 

 grays containing white lead. 



" A study of the yellow panels on the fence led to the unani- 

 mous conclusion that a liberal amount of Basic Carbonate- White 

 Lead seemed to have a beneficial result in preserving the bright 

 tone of the chrome yellow in tints so strong as those used on the 

 fence. It was noted that Panel 108, which represents Formula 

 28, and in which zinc yellow was used, showed great permanence 

 of tone and tint. Unfortunately this zinc chromate was added 

 to a formula containing a large percentage of lithopone, and the 

 destruction of the lithopone to a great extent affected the value 

 of this test. 



" Maintenance of Para Reds. A study of the paranitraniline 

 or azo reds painted over the various pigments as priming coats 

 demonstrated that the reds on this fence are in better condition 

 than the reds at Atlantic City. As is well known, para red is 

 manufactured by precipitation in an acid solution and is best 



