Basic Knowledge of Color Matching for Car Spray Painting

The common sense of car paint color matching is as follows:

1. Light

2. Objects

3. Investigator

4. The interaction between the three major elements

5. Light source discoloration

6. Standardize light sources and visual colorimetry

7. Nature of Color

8. Varieties and Changes in Colors

9. Color allocation

1. Light

a. The composition of light is an electromagnetic radiation and also an electromagnetic wave. The light we usually see is called visible light, with a wavelength range of 400-700nm. Outside this range, there are also ultraviolet and infrared rays.

b. The composition of white light: Clean white light is composed of six colors: red, orange, yellow, green, blue, and purple, all of which constitute the spectrum.

c. The composition of object color: The surface of an object contains pigments, which selectively reflect some light and also absorb other light. Pigments determine the color of the object. The color of non transparent objects is reflected by the color of the reflected light, such as white light shining on objects containing red pigment, which can only reflect red light. Therefore, red color was investigated. If there are both red and yellow pigments, investigate orange. Transparent bodies are reflected by the color of the light they pass through. White pigments can reflect all light, while black pigments cannot reflect any light.

d. There are two types of light sources: natural light sources and artificial light sources. The spectral curve of sunlight tends to be higher at the blue end of the spectrum, so sunlight is essentially somewhat bluish. The wavelength of incandescent lamps tends to reach its peak at the red end of the spectrum, which belongs to warmer light. The curve of a fluorescent lamp emits more energy in the blue part of visible light, which belongs to colder light. After sunrise and 3 hours before sunset are good times to investigate and analyze colors.

2. Objects

Objects can be divided into two categories: luminescent and non luminescent. When a light source illuminates a non luminescent object, the object reflects, transmits, and absorbs three reactions to the light shining on its surface, thus forming a distinct color sensation. If an object contains pigment, the pigment will selectively reflect some light and absorb other light. The reflected light determines the color of the object.

3. Investigator

The visual characteristics of the investigator's eyes are the physiological basis for color perception. A person with normal color perception ability perceives the visible spectrum as a series of consecutive colors, in the order of dark red, bright red, orange, yellow, bright green, green, blue, and dark purple. People's perception of color is subjective, and people with color vision defects cannot correctly distinguish colors, so they are not suitable for color mixing work. Due to the fact that women have a stronger perception of color than men, have a lower probability of developing color blindness, and have the characteristic of being meticulous, most of the workers engaged in color mixing and measurement are women.

4. The interaction between the three major elements

Color is a combination of object reflection, light source, and investigator. If any of these three factors are changed, the colors that occur will also change accordingly.

5. Light source discoloration

Light source discoloration: Two objects exhibit the same color under a certain light source, but when investigated under different light sources, significant color differences may occur. The fundamental reason is that the pigments contained in the object are different, and the intensity of various colored lights in different light sources is also different. So it is necessary to verify the color matching under the conditions of light sources that may cause color change. The occurrence of this phenomenon in color mixing may be due to the difference in pigments used in the repair paint and the original paint formula, resulting in different colors under different light sources. Therefore, it is necessary to add color matching agents to the formula for treatment.

6. Standardize light sources and visual colorimetry

Standard light source: The light source agreed upon by the color operator. The 'standard illumination body A' represents the light of a completely radiating body with a temperature of approximately 2856K; The 'standard illumination body B' represents direct sunlight with a relevant color temperature of approximately 4874K, equivalent to noon sunlight; The 'standard illuminant C' represents the average daytime light with a relevant color temperature of approximately 6774K; The 'standardized illumination body D65' represents a daylight phase with a relevant color temperature of approximately 6504K.

Visual colorimetry is the process of arranging the colors of a sample and the colors of the sample together, and using the naked eye to investigate whether they are the same. Visual colorimetric lighting uses natural light from 3 hours after sunrise to 3 hours before sunset to prevent direct sunlight, and selects light from the northern window. The angle between the field of view and the light is 45 °, and one of the items between the field of view and the light is straight with the sample. The result of color comparison, if two color samples are thoroughly isochromatic under any light source investigation, is called homochromatic and homospectral; If two samples are investigated to be of equal color under one light source and unequal color under another light source, this phenomenon is called homochromatic metamerism.

7. Nature of Color

The nature of color is color, brightness, and chromaticity, also known as the three spatial or three color attributes of color. To fully and accurately describe a color, it is necessary to include these three aspects, which are indispensable.

a. Color (also known as hue) is the difference between colors, which refers to the color appearance of monochromatic light at a certain wavelength. Color is a property (attribute) of color that allows us to depict objects as red, orange, yellow, green, blue, and purple. The fundamental colors in the color system are red, yellow, and blue, also known as the "three primary colors", and almost all colors can be assigned using them. Orange, green, and purple are the three primary colors of red, yellow, and blue, distributed in pairs in a 1:1 ratio, known as the "three intermediate colors". These six colors are collectively referred to as the six fundamental colors of color. If viewed from the perspective of chromatic light, the color changes with the wavelength. Purple red, red, and orange are all specific colors in the red category, and the differences between these three types of red belong to different colors. The same color may be darker or lighter.

Article source: Qingyuan Automotive Repair Paint http://www.jinliangxincai.com/