How to calculate the color difference of colorimeter?

First of all, we need to know what lab is, because the color difference calculation of colorimeter is inseparable from the lab value; CIE in 1976 recommended CIE1976 L * a * b * color space, also known as CIELAB color space, which is mainly used for the representation and evaluation of hypoblend colors such as surface pigment industry. The following is the formula of color difference calculation method of colorimeter:
Calculation formula of color difference data △ E: △ E *=[(△ L *) 2+(△ a *) 2.+(△ b *) 2] 1/2.
△ E is calculated by the formula in the international standard color space L * a * b.
L *=measuring light source * observer angle * optical structure * sensor accuracy * sample;
A *=measuring light source * observer angle * optical structure * sensor accuracy * sample;
B *=measuring light source * observer angle * optical structure * sensor accuracy * sample;

While △ E *=[(△ L *) 2+(△ a *) 2.+(△ b *) 2] 1/2 color difference data △ E calculated from the color difference data of the colorimeter is the color difference between the product and the sample. Then we can see the lack of color through △ L, △ a and △ b, and adjust the color quality through subsequent repair and process optimization, so as to achieve the way of product color difference control.

We know that color difference is relative when measuring color difference. Is there any color difference relative to the standard color. Then this formula is simply (L standard color – L measuring color) 2+(a standard color – a measuring color) 2+(b standard color – b measuring color) 2. Then the sum obtained from the above data is extracted. So when Δ When L is a positive value, it means that the tested sample is brighter than the standard sample, and when L is a negative value, it is darker. Δ When a is a positive value, the color is more red than the measured color (that is, the red color indicated in our instrument is less green), Δ When a is negative, it is green with less red. Δ When b is positive, it is yellow with less blue Δ When b is negative, it is blue with less yellow.

In addition to △ E, the color difference formula also includes Δ E*ab、 Δ E*uv、 Δ E*94、 Δ E*cmc(2:1)、 Δ E*cmc(1:1)、 Δ E * 00, the most common is Δ E. Apart from him Δ E * uv is also common. Let’s add that, Δ In the E * uv color difference formula, “U and V” represent chromaticity. The chromaticity range is – 100 to+100. and Δ The value of E * uv is exactly obtained from the tristimulus values of X, Y and Z. So it is also applicable to the variance formula.

So the above is the solution of how to calculate the color difference data △ E of the colorimeter, including the explanation of the color difference formula. LISUN lauched Portable Colorimeter/Chroma Meter is an innovation color measuring tool with powerful configuration to make color measurement easier and more professional; It support Bluetooth to connect with Android and ISO devices, Portable Colorimeter/Chroma Meter will take you into a new world of color management; It can be widely used to measure color value, color difference value and find similar color from color cards for printing industry, paint industry, textile industry, etc.

Introductions:
Measure Color Value
•Adopt international used D/8 (Diffused Illumination, 8 degree viewing) geometry and SCI mode to make measurement more accurate.
• Adopt spectral sensor to provide reflectance data which make its performance much better than colorimeter.
• To get correct L*a*b, L*Ch, RGB, Hex and other color value under light source D65 or D50.
• It can measure whiteness index, yellowness index, color strength, color fastness, opacity and other 20 kinds of parameters with 26 kinds of illuminants.

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