The theory of chromaticity is relatively mature, and its application in the field of cultural relics protection and restoration has been developed. The restoration effect of ancient ceramics is greatly affected by the light source. The light source of the restoration room does not match the light source of the exhibition hall, which may lead to unsatisfactory restoration visual effects. The theoretical method, with the help of a portable colorimeter, can improve the color rendering effect of objects under different light sources.
The color matching process of ancient ceramic restoration is called conditional color matching. Under a specific light source, a pair of objects with different light waves can produce the same color. Therefore, once the light source changes, the color difference between the restoration and the body is inevitable. The purpose is to improve this phenomenon. The color method can be learned from the Munsell color system. First consider the brightness of the color, the system called brightness, that is, the grayscale change process from white to black, which is the performance of the amount of reflected light on the surface of the object. There are many kinds of ancient Chinese ceramics, and there are many high and low brightness utensils. It is one of the keys to mastering the adjustment of brightness. The second is saturation, which is most obvious on pastel and multicolored objects. By adjusting the saturation, the brightness can also be changed. The last is transparency. When simulating the glaze color, transparency is the characteristic of the enamel. When the transparency is increased, the reflection of the light is reduced, and the brightness will naturally decrease. The angle of the light source has a huge impact on the color of ancient ceramics. It is the purpose of the color system of ancient ceramics to weigh the relationship between various aspects and adjust the most reasonable ratio.
The final restoration color, or restoration, theoretically means that the incident light from the main light source reaches the restoration base color layer and no longer transmits, or the reflected photoresist enters the glaze layer, and its color depends on the base color and the glaze color.
The role of the colorimeter is limited because there are many kinds of ceramic glaze colors, the thickness of the glaze layer is different, and the amount of reflected light is different, but the colorimeter is to test the reflected color and color difference, so it is suitable for the application of ancient ceramic restoration and coloring. Using a portable colorimeter, this instrument is easy to use and has high accuracy. Compared with ordinary colorimeters, it is much more accurate. The instrument can adjust light sources of different spectra and select different color temperatures, which represent the color temperature of the light source in the exhibition hall and the laboratory (simulating sunny days). Daylight) The color temperature of the light source. The color rendering of blue and white porcelain varies significantly at different color temperatures.
The colorimeter provides a more accurate color difference value, which clarifies the direction of color adjustment. According to the tasks and requirements of the restoration work, the color can be selected to fully meet the requirements of the light source of the exhibition hall. With the help of a colorimeter, works that meet the color requirements of the exhibition hall can be accurately completed and can be inspected and accepted by the handheld color meter.
The color of the utensils is the manifestation of the visible light selectively absorbed and reflected. Because the restoration material is different from the material of the ceramic itself, the two absorb and reflect different wavelengths of colored light differently, and the color presented is definitely different. A colorimeter can help reduce the influence of different light sources on color rendering, but the final restoration effect is not only a matter of color and gloss but also the texture, mechanism, and transition effect of the porcelain still need to be given by the restorer.