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Tinting Basics (Mixing Colors) - Colorimetry
Example of mechanical color measuring device (Computerized color measuring machine)
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Comparison of two different colors is Colorimetry, which is very important for paint repair. There are two methods to do Colorimetry. One is visual comparison and the other is by using a colorimeter. During paint repair, especially for metallic and pearl colors, it is extremely difficult to use a mechanical device to accurately measure color. The visual approach is most common in shops.
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Visual Color Colorimetry:
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Vehicles are viewed under all sorts of light sources including the sunlight, florescent light, mercury lamp, etc. The repaired color on a car body must be perfectly matched with the surrounding color under any light source. Therefore, the mixed color must be compared under all possible light sources. | |
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The color of the light source is stipulated by CIE (Committee of International Electric Lighting). | |
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A light source: Electric light equivalent to that of a tungsten electric bulb.
B light source: Light equivalent to that of the direct sunlight at noontime.
C light source: Daylight including the light from the blue sky.
D65 light source: Artificial light equivalent to the light at noontime.
(Source) CIE light sources
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When comparing colors, it is not sufficient to check the color only from one particular angle. For metallic and pearl colors in particular, the color will look different according to the direction of sight. Always check colors from different angles.
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Angles to check and their terms
Check basic colors from the following angles: |
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Conditional Identical Color (Metamerism):
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A phenomenon where two different colors look the same under a certain light source. This phenomenon occurs because of the spectral diffraction between the two colors. To avoid errors caused by this phenomenon, always use the same color pigments as those used in the color samples. | |
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In order to confirm whether the colors are conditionally identical or not, compare the colors under the natural light (outdoors), and then again under the florescent and/or infrared lights (indoors). | | |
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A phenomenon where two colors that look the same from a certain angle are seen differently when viewed from different angles. This phenomenon is caused by the differences in the levels of transparency caused by the kinds and sizes of pigment used.
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It often happens that the two colors look the same when viewed straight ahead, but different when viewed at an angle.
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