Influence of lighting direction on measured brightness values of colored objects
Currently, there are many ways to collect architectural colors. One of the popular methods is the digital color collection from images. However, the factors of lighting direction and building location were not combined with this method, which is an important factor affecting the measured color value different from the original color. Therefore, this research aimed to investigate the changes in color brightness when the light shines on the objects with different directions by collecting the colors from 5 different color cube models and analyze the color value of each side. The result illustrates that when the direction of the light changes in the vertical from 0 degrees to 30 and 60 degrees, color brightness mostly decreases by not more than 15 percent. However, when the vertical direction of the light changes from 60 degrees to 90 degrees, the brightness of all colors decreases by an average of 80 percent, which directly affects white and black. In addition, this study also found that the factors of hue and saturation affect the yellow, red and blue, in particular, the saturation of the yellow is measured lower than the preliminary color by 50 percent. While the saturation of red and blue are different to primary colors that are less than 20 percent. This research has been applied with the digital color collection architecture in Songkla Old Town, by analyzing with the sun direction, building location and the color brightness. In order to be more precise, the experiment should study various types of colors, model and the analysis of hue and saturation.
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