Color assessment of granitic rocks and implications for their ornamental utilization
Ficheiros
Data
2012
Autores
Sousa, L.M.O.
Título da revista
ISSN da revista
Título do Volume
Editora
Wiley
Resumo
The purpose of this study is to evaluate the factors
affecting the assessment of granite color, such as
grain size and texture, and to propose a methodology for
this task which would reduce the margin of error associated
with this procedure. For this purpose, an evaluation
was carried out on the color of several granites with different
textures used in the dimensional stone industry to
highlight the importance of the sample area, the number
of measurements per sample and the aperture of the
equipment. A colorimeter was used to measure the granite
color according to the CIE-L*a*b* and CIE-L*C*abhab
systems, in both large slabs and small samples selected in
a processing plant of ornamental granites. Granite color
characteristics from large slabs had to be obtained with
at least 60 shots due to the variation between different
slabs. Therefore, several samples are needed for granite
characterization. The color of gray granites does not vary
significantly. Nevertheless, the more weathered granites
show significant differences which are more evident in the
b*-parameter, or the yellow–blue component, which allow
the use of the colorimeter for quality control. By doing so
significant differences among the rock pieces used in a
single building can be avoided. There were no significant
differences found in the color parameters from distinct
apertures. However, due to the heterogeneity of the granite
the color is evaluated better with larger apertures.
Descrição
Palavras-chave
colour , granite
Citação
Color Research & Application, vol 37, nº 5, pp. 375-383