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The distance from lamps to the samples was 1,5m, and samples
were uniformly illuminated with the illminance of 7500 lux.
Lamps were changed with new ones every four day to keep
constant the illumination. Samples were also suffered
from the heat. Its temperature taised up to 40°C.
3) Exposure test by Fad-O-Meter
This instrument are adopted to the fading test for
textiles and pigments, Its 100 hour exposures are saik
to be equivalent to one year exposure of natural daylight.
The test was carried out 10 hours a day for 10 days,.
The temperature of samples raised up to more than 50°C,
Color of color film depends on the amounts of the three,
cyan, magenta and yellow dyes in each sensitive layer of the
Color film, The amount of cyan is determined by the
red density, magenta by the green density and yellow by the
blue density. So, the color fading, Tp, was evaluated
by the ratio of each color density before and after the
exposure;
Do T
(9
where, Dg is color density after the exposure and D, is
color density before the exposure,
The change in color depends on the amount of the color
dyes and fading rate deffers from the color to another,
Much yellow dye was contained in saturated Red (R2),
the saturated Green(G2) and the dark grey. On the
contrary, less yellow dye in the pale Red (R1), pale Green
(Gl) and light Grey(N1),. SO color measurements were
separately for the pale color group and the saturated color
group.
The saturated color group always faded much more than
the pale color group except Chibachrome CCT and Kodak 2447,
Cyan dye was most resistive for fading test and yellow dye
was the worst. | ;
After exposing for 100 hours by the Fad-O-Meter, yellow (*
dye faded about 60$-70$ of the original dye amount,and its
color was almostly invisible, Magenta!s fading loss was
20$ in the saturated color and 40$ in the pale color.
Cyan dye's loss was only 10%, Accordingly, faded color
film becomes blue.
There were some differences in fading rate among three
methods, but no differences in the tendency of fading and
in respect of yellow dye, 30 day's exposure by tangsten
lamps was equivalent 30 - 20 hours exposure of the Fad-O-Meter
and 30 days' exposures of the natural sun light to 70-80
hours' of Fad-O-Meter,
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