1. Introduction

Color, as a manifestation of vision, is the perception produced by human eyes under different wavelengths of light. In the field of coating, the color of the coating film refers to the color reflected or projected by the surface under light irradiation after absorption, reflection, refraction, etc. The measurement of coating color is of great significance for evaluating coating effect, quality control and conformity with standard.

2. Relevant standards

GB/T 9761 and ISO 3668 are national and international standards related to the color determination of paints and varnishes, which provide accurate specifications and methods for the color determination of coating films.

3. Introduction of key points of inspection methods

3.1 GB/T 9761 color paints and varnishes Visual comparison of color paints

3.1.1 Test principles

The method compares the sample template with the standard sample template (or standard color card) under a certain light source (such as natural or artificial sunlight) to assess the color difference between them.

Paint film color determination method summary notes

3.1.2 Materials and instruments

The substrate needs to be flat, such as tinplate, duralumin, steel or glass plate; Samples and standard samples (or standard color cards); Comparator box and other equipment.

3.1.3 Operation Points

Preparation template: Prepare sample template and standard sample template, construction and drying under the same conditions.

Color comparison procedure: the sample template and the standard sample template (or standard color card) are placed side by side, using natural daylight or artificial daylight for color comparison. To observe the color difference, the distance between the eye and the template is generally about 500mm.

Evaluation of conditional color matching: For samples and standard samples containing different pigment composition, it is necessary to observe under the CIE standard light source D65 and A (tungsten lamp) to determine whether the color is equal.

3.1.4 Result presentation

The result is whether the color is consistent.

Paint film color determination method summary notes

3.1.5 Precautions

The observer must have normal vision and no visual impairment.

The continuous color comparison time of the observer should not be too long to avoid eye fatigue.

After observing strong colors, avoid looking at light or complementary colors immediately, and observe neutral gray for a few seconds before continuing to compare colors.

Observers should wear neutral clothing and compare colors in a neutral gray environment to avoid the reflected light of colored objects affecting the results.

4. Application and significance of the method

Film color measurement is an important method to evaluate film color. By this method, the difference between the color of the coating sample and the standard sample can be compared under the standard light source, so as to ensure that the color of the coating is consistent with the design requirements and improve the product quality.

5. Conclusion

The method of film color determination is of great significance to ensure the consistency of film color and the accurate control of film quality. Using this method, the color difference of coating film can be evaluated objectively and accurately, and reliable data support can be provided for the quality control of coating engineering to ensure that the coating film meets the design and standard requirements