Effect Of Type Of Illumination In Color Measurement

Color measurement is one of the most commonly used experimental methods which is used for analyzing the quality of the products. The color measuring gives valuable data about the quality and features of a materials or product. The manufacturers need to use the best instruments such as colorimeters or portable spectrophotometers to conduct the procedures of color measurement on the test specimen to ensure that the analytical data they obtain from eth instruments are of best quality.

One of the major factors that affect the accuracy and precision of the test data in color measurement is the type of illumination and the angle of illumination that is used for the analysis. Many different types of illuminants used for the experiment and analysis that are discussed below.

The angle of illumination

The angle of illumination can cause variation in the intensity of light at which the object appears. The same object may appear darker, lighter, brighter or dull at the different angles of illumination. In order to analyze the various attributes of the object, it is essential that same angle of illumination is used throughout the experiment. There are two types of illumination systems used in the color measuring instruments that are unidirectional illumination system and the Diffused Illumination integrating sphere system.

Unidirectional Illumination systems

The unidirectional illumination systems use a single angle for illumination of the object, and any other reflected light is excluded by the system. These systems are very sensitive to the conditions of the surface hence are best for measuring the sample color rather than the true color of the sample.

The unidirectional illumination system can be used for the following purpose

1. The evaluation of the quality control which ensures that every batch of the products has the same quality.
2. Measuring the color of the glossy and shiny surfaces.
3. For the comparison of the samples having a similar texture, gloss or conditions of the surface so that there is the consistency of the quality and appearance.

The most commonly used unidirectional illumination systems are 45⁰ and 0⁰.

Diffused Illumination Integrating Sphere Systems 

This type of illumination is used for illuminating the objects uniformly from every direction. This type of instruments can be used along with the specular component included mode or the specular component excluded mode as per the requirements of the test procedure.

This type of illumination can be used for the formulation of chemical compounds that meet the color requirements, to measure the color of the samples having highly textured and rough surfaces.

Testronix offers the best range of color measuring instruments such as portable spectrophotometers and colorimeters that are capable of providing efficient illumination of both Uniform and diffusion type that ensure accurate color analysis of the products.