138 PAINT TECHNOLOGY AND TESTS 



must be designed with relation to the particular uses of the 

 product and to the climate in which they are to be used. It 

 will also be necessary to consider more carefully the vehicle of 

 the paints which are to be made of this pigment. 



" Possible Value of Excluding Vehicle for Lithopone. It was 

 the belief of the committee that much better paints containing 

 lithopone could be designed by varying the percentages of the 

 materials contained in the formulas, and it was suggested that 

 a less penetrable vehicle, made more on the line of a varnish, 

 and not as easily affected as straight linoxyn, should be experi- 

 mented with in connection with these lithopone formulas. 



" The success of certain European countries in using lithopone 

 as a pigment, even in a very high percentage, may be due to the 

 use of a special vehicle, and, if it is found in future tests that this 

 material, which has been reported as well suited in Northern 

 European climates, may be benefited and made of service by 

 the addition of special oils and special vehicles, then this test 

 would be of great value to the whole paint trade at large. 



" Preliminary inspections were made on October 6th and 

 later on December 12th, 1908, and a marked difference was ob- 

 served at the two inspections in the wearing of the various 

 formulas. 



" The lapse of the two months between these inspections gave 

 opportunity during which cold weather caused contraction of 

 the paint film which had been previously subjected to the hot 

 summer sun, and caused marked chalking of the white lead 

 formulas. On October 6th this chalking was just commencing, 

 while in the December inspection it was well advanced, and at 

 the annual inspection, had proceeded to such an extent that the 

 pigment had been washed from the panels representing those 

 paints which had started early chalking. 



" Panel 177, representing Zinc Lead, was found to be ex- 

 tremely dark in color throughout the coating and was more on 

 the order of a grayish tint. It resisted all attempts to wash it 

 down to a white surface. The panel, however, in other respects, 

 was in fairly good condition. 



" Condition of Corroded White Lead Panels. Panel 174, 

 representing Type B Pure Basic Carbonate- White Lead, was 

 very badly perished and discolored, and an examination of the 

 surface showed very bad checking. Long continued washing 





