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IOWA ACADEMY OF SCIENCE Vor.. XXVII, 1920 
9. Light greens. All showed change; a few very much. 
10. Reds. All showed great change, the light ones and pinks 
having faded nearly white. 
11. Light blues. All faded nearly white. 
The foregoing is offered as the rule for the stability of colors 
in wallpaper, to which, like most rules, there are evident excep- 
tions. These exceptions are probably due to a difference in the 
chemical material composing the coloring matter. It was observed 
that the light shades were more prone to fade than dark ones. 
The higher priced papers were more permanent than the cheaper 
ones, with a few exceptions. Gilts and micas were apparently un- 
changed. Red, pink, green and purple decorations, on any back- 
ground, faded. 
The question may arise as to the colors that were assumed in 
fading, that is, the colors resultant from fading. Specimens of 
the same papers were exposed during the spring, each for several 
days, to the strong light of the show window, and sometimes in 
the direct rays of the sun. The dark or deep reds became a dark 
purple, some of them of pinkish purple hue; the light reds be- 
came a light pink. The dark greens assumed a genuine slate 
color; the light greens approached white, some of them with a 
yellowish tinge. The drabs became lighter, approaching white. 
The browns assumed a dark reddish drab. Even the whites 
assumed a cream tint, which is, probably, the ultimate color into 
which a majority of all the other colors would finally fade. 
When colored glass was placed over a light blue paper, the 
paper faded least under the green glass and most under the purple 
glass. When a red paper was treated in a similar manner, it 
faded least under the red glass and most under the green glass. 
It is doubtful if there is any color used in wallpaper that is 
absolutely permanent. However, the gilt and mica, or the gold 
and silver, on- the specimens subjected to the long-time exposure, 
showed no alteration. 
Perhaps, the most permanent wallpaper would be that with a 
white or buff background with gilt and mica decorations. 
Winfield, Iowa. 
