Visual
reflectance
Spectral reflectance
Color reproduction
Aluminum mirror
84.8
For the low Spectral
reflectance in the long
wavelength range, the iamge
gives a cold and hard
impression.
Not suitable as a
cosmetic mirrors for the faces,
skins, and make-up
cosmetics.
Cold blue tone is
emphasized.
The image gives a cold and
hard impression.
Silver
mirror
94.2

Spectral reflectance in the
long wavelength range is high.
This mirror gives a precise
and abundant color
reproduction in the warm
color region something like
faces and skins.

Warm color family -YR
(yellowish-red) tone can be
reproduced excellently.
This spectral property affects
the color reproduction
of the faces ,
skins and make-up
cosmetics with warm and
soft feeling.
Comparison
of spectral
refletance
10 %
higher

* These test samples were manufactured by Hankuk Corp.,Ltd.
shows the spectroscopic comparison between silver and aluminum mirror. As we can see in the Figure, in the long wavelength range over the 500 nm, the difference of the spectral reflectances between the two mirrors was greater than 10 %. And in the UV range silver mirror shows a remarkable capability to cut off UV.
When we compare the visual reflectance, there is something that should be kept in mind. The Y value of CIE XYZ means the relative quantity of the reflected light from the mirror. There is some thing different between the visual reflectance and the brightness that people feels actually and measured with psychophysical method. The brightness, perceived psychophysical quantity, is coincident with L* value of CIE LAB.


Table 1 shows the comparison of the visual reflectance and brightness between the silver and the aluminum mirror.
Mirror
Visual reflectance
(CIE Y)
Brightness of image (CIE L*)
Aluminum
84.8
93.8
Silver
94.2
97.6
According to the table, the visual reflectance of the silver mirror is 10 % greater than that of the aluminum mirror. And the perceptional difference of the brightness is 4 %. These means, the reflected light of aluminum mirror is 10 % less than that of silver mirror and this makes the brightness difference of the human perception by 4 %.

shows the comparison of the color between the two mirrors (Al/Ag mirror). The color of silver mirror has a warmer color than that of Aluminum mirror. This reflective character affects the images in the mirror as silver mirror can reproduce the warm color family more abundantly. In contrast, the blue tone is emphasized in the aluminum mirror. This makes the images in the mirror hard and cold. So it is not recommendable that the aluminum mirror is used for the observation of the faces, skin, and the condition of color cosmetics.
The character of color reproduction which gives more direct emotional effect, is more important than the brightness. Especially for the mirror of cosmetics which is required for a detail color and a sensitive mood, it becomes a major scale of evaluation.
Fig. 5. is the photograph that shows the images of the silver and the aluminum mirror of the same face. By a close inspection, you can recognize that the right side image gives more soft and warm feeling.
This comes from the fact that silver mirror gives abundant light in the long wavelength range so there are no color distortion of the spectroscopic like the left aluminum mirror.
(July 25th,2005 Korea Research Institute of Standards and Science)
 
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