ZEMCH 2019 International Conference Proceedings April.2020 | Page 280
respectively. Two additives, refractive index liquid (n=1.550, Cargille laboratories, Inc.) and distilled
water were tested.
Reflected light was observed in the same 10cm distance from the sample surface to the spectral sensor
and chromameter. 80W 6500K white LED light bulb was used for light source.
3. Results
3.1. Color Detection
Figure 1 and upper part of Figure 2 shows the chromaticity diagram of five samples. As denoted
in figures, all samples were prepared as dried, water added, and refractive index liquid added. Water
and refractive index liquid were utilized to investigate the effect of additives on the reflected light by
Table 1. Chromaticity values of household dust measured under experimental conditions
Sample
As
prepared
Household
Dust
Refractive
Index
Liquid
Added
Filter
‐
Red
Orange
Yellow
Green
Blue
Pink
Violet
‐
Red
Orange
Yellow
Chromaticity Values
Y
X
y
13.40
0.3229
0.3244
4.87
0.4216
0.3307
8.01
0.4625
0.3576
13.47
0.4230
0.4305
5.08
0.2923
0.3853
3.16
0.2516
0.2058
9.91
0.4098
0.2624
4.40
0.2970
0.2686
3.48
0.3163
0.3177
4.37
0.3768
0.3369
5.87
0.3859
0.3305
8.17
0.3756
0.3864
Sample
Water
Added
Green
Blue
Pink
Violet
Chromaticity Values
Y
X
5.18
0.3190
4.43
0.3869
6.16
0.4197
9.02
0.3955
4.41
0.3025
3.11
0.2692
8.52
0.4081
4.35
0.3008
3.92
0.3021
4.29
0.2800
7.38
0.4170
3.39
0.3080
y
0.3208
0.3357
0.3508
0.4066
0.3586
0.2320
0.2856
0.2851
0.3635
0.2699
0.2834
0.2797
changing refractive indices and color as well. As explained in materials part, cellophane filter which
can block specific range of wavelength depending on its color. As prepared samples, denoted to circle
in diagram, were observed to locate at the matching color region according to color of cellophane filter.
Details of chromaticity values for household dust are summarized in Table 1. Noticeable difference was
measured for white color powders such as talc and gypsum samples. For white color powders, more
distinct shift to each color regions were measured rather than yellowish pollen, soil and grey household
dust. It may be attributed to the intrinsic color of powder is close to white, more light reflected to the
detector and induced to increased intensity to the spectral sensor.
(a)
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(b)
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