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The
research project aims at the development of a color communication system
for gemstones by replacing the common color names such as pigeon blood
red, cobalt blue, lemon yellow which cannot represent the true meaning
of color with the standard color names that are used internationally in
other industries such as textiles and printing. The gemstones used in
this project were emerald, yellow sapphire, amethyst, garnet, topaz, tanzanite
and pink sapphire. Altogether seventeen sets of standard gemstones weighing
from 0.75 to 1 carat were obtained by careful selection based on three
criteria : attractive color, brilliance and transparency. The quality
and authenticity of the standard gemstones were also determined by the
following instrumentation procedures: refractometer, microscope, UV-VIS-NIR
spectrophotometer and EDXRF spectrometer. Each master stone set is color
matched to Munsell color chips in the standard lightbox Gretag Macbeth
model The Judge II, color temperature 5000 K. The illuminance at the study
area is 1200 lux. The Munsell color code of each master stone is transformed
into the color preference survey. The information obtained indicates significant
differences in color preference among people of different nationalities
(Thai, european, American, Australian, African and other Asians).
In normal practice, GIT uses these standard sets
of gemstones and their color codes and names as master standard gemstones
to conduct subjective color matching and grading with customer's gemstones.
The visual Munsell color description was correlated
with instrumental measurement of a color by using a spectrophotometer.
The results of the new gemstone grading system are accurate enough to
satisfy a scientist and usable enough to satisfy manufacturers and traders.
The results of this research help enhance the standard and quality of
the Thai gem and jewelry industry and are useful in marketing and export. |
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