Nine kinds of blue pigments were blended in a varnish with titanium white at ten levels of weight ratio (four repetitions). These pastes were painted both on the faces of the paper and the transparent film. The luminous reflectance of these painted strips were measured and transformed to Munsell value VY. If it is statistically acceptable that the VY-log (wt. ratio) plots for these pigments are straight and parallel with each other, the tinting strength of the pigments can be computed. The purpose of this paper is to investigate the suitable limits of this condition. Following results on the regression analysis between four levels of weight ratio were shown. 1) Seven of the nine kinds of the blue pigments were suitable between 0.46 and 4.6 (wt. ratio of the white pigment by the blue pigment) when they were painted on the paper, and between 0.22 and 2.2 when on the transparent film. 2) The other two pigments were suitable between 10 and 100 both on the paper and the film.
A series of glossy finishes pigmented with an organic red pigment and a rutile titanium dioxide was exposed simultaneously in Florida in the United States, Okinawa and Awaji Island in Japan. The panels were examined periodically on gloss and color changes during the exposure period. The gloss retention was the highest in Florida where the solar radiation was the greatest among these locations. The lower values in gloss retention in Okinawa and Awaji Isl. might be attributed to the heavier rainfall and longer sunshine hours in these locations. When the color was measured without polishing the exposed panels, the color change in Okinawa was about the same degree as that in Florida, and in Awaji Isl., that was slightly less. The color changes in this measurement might be affected by both the haze on the paint surface and the fading of the red pigment in the film. When the measurement was done after polishing the panels, the color change was the greatest in Florida. In Okinawa and Awaji Isl., these were respectively about 80% and 60% of that in Florida. These values, which might be resulted mainly from the fading of the red pigment, were nearly proportional to the amount of solar radiation in each location.