How to calculate the color difference value with spectral colorimeter in the spray industry
Each industry has a set of industrial color difference requirements, especially in the spray industry, customers have higher requirements for color difference, they require that the color difference of the spray must be within a certain range, which is a lot of people. The color difference value ΔE is quite valued. So what is the value of △E in the range?
Here we take spectral colorimeter as an example to explain in detail to everyone. The main components of the colorimeter are: light source, integrating sphere, grating, photodetector and color measurement software. If there are two sets of data measured, respectively, the L, A, B values of the sample and the standard, △ represents the change, then the color difference The calculation formula of △E is:
△L=L sample-L standard (lightness difference)
△a=a sample-a standard (red/green difference)
△b=b sample-b standard (yellow/blue difference)
We know that the color difference calculation formula is not enough, and we must not understand the meaning of the expression, in order to better grasp the standard range of the color difference value △E.
Generally, we use ΔE to indicate the magnitude of the total chromatic aberration. The smaller the value, the smaller the chromatic aberration, the ΔL is the degree of black and white, Δa is the difference between red and green, and Δb is the difference between yellow and blue.
△L+ means white, △L- means black
△a+ means reddish, △a- means greenish
△b+ means yellowish, △b- means bluish
Each customer’s standard range for △E requirements is different, and the requirements of △E for different industries are not the same, but in general they can be divided into the following stages:
0 – 0.25△E
The range of ΔE values is in the above range, representing very small or no; ideal match
0.25 – 0.5△E
The range of ΔE values is in the above range, representing a small; acceptable match
The range of ΔE values is in the above range, representing small to medium; acceptable in some industry applications.
The range of ΔE values is in the above range, representing medium; acceptable in specific industry applications
2.0 – 4.0△E
The range of ΔE values is in the above range, representing a gap; acceptable in very few industry-specific applications
4.0△E or more
The range of ΔE values is in the above range, which represents very large; basically unacceptable
In the spraying industry, the manufacturer must know the scope of the customer’s requirements for the product. After the value measured by the spectral colorimeter is submitted to him for confirmation, the product will not be rejected because it does not meet the requirements.