How does a Colorimeter calculate ink thickness?

Using the density detection formula in the Colorimeter or using the spectrodensitometer to measure the ink problem in the printing industry, the calculation formula is the same, but the measurement form is different, and the result is still the same.

How does the Colorimeter calculate the ink thickness?  Picture 1

The use density value caused by the nature of the ink itself is not directly proportional to the thickness, but presents a more complex relationship model, and is also related to the size of the paper. Experiments have proved that the optical density D of the ink does not increase infinitely because of the thickness of the ink. There is a saturation value here. Using a Colorimeter or a densitometer to detect, we will find that when the ink thickness is around 10μ, the light intensity is basically in a stable state, that is, it has reached a saturated state. Assuming the density value at saturation state, the following relationship can be written:


dD=m(D∞-D)·dl

After integration and sorting, there is: D=D∞(1-e-ml) where m is a constant related to the smoothness of printing paper.

In the formula, the density D and ink thickness l can be determined experimentally, so that the other two parameters D∞-1 and m in the formula can be obtained.

For example, use newsprint on the printing suitability Tester (IGT), carry out embossing with l1=1.097μ, l2=2.194μ, and measure the corresponding density as D1=0.69, D2=1.01, then the equation can be written according to the appeal equation :

D1=D∞(1-e-ml1)


Eliminating D∞l, we have

D1=1-e-ml1/1-e-ml2·D2

0.69=1-e-mx1.097/1-e-mx2.194×1.01

D2=D∞(1-e-ml2)


Solve the equation to find the paper smoothness constant

m=0.571

The density value at the saturation state can be obtained from the formula above:

D∞=D1/(1-e-ml1)=0.69/(1-e-0.57lx1.097)=1.484

Substituting the obtained parameters D∞ and m into the formula, the calculation formula for the relationship between ink density and thickness suitable for newsprint can be obtained:

D=1.484 (1-e-0.571l)


The Lambert-Beer law we know is launched under satisfactory conditions. We know that it is impossible in real life to fully satisfy the calculation conditions. This law only considers the absorption of ink, without many factors in the actual printing process. Not to mention the influence of substrate paper, plastic, etc. on ink transfer and color quality, so there are differences between theoretical calculations and actual densitometer or Colorimeter measurement results. However, although the actual situation varies widely and there are many types of influencing factors, "absorption" is still the root cause of the ink's fineness.

In addition to providing different series of color measuring instruments, ink Colorimeter manufacturers will also provide a variety of supporting products, such as quality control software, color database management module, customer management module, color standard data management module, etc. In terms of hardware, there are also useful Optional accessories for special sample measurement. The supporting products of the Colorimeter can make the function of the Colorimeter more perfect in quality inspection, management and production. Even if some functions are not needed temporarily, but in the long run, once the system is upgraded, it only needs to add supporting products without being restricted by the color measuring instrument itself.

The manufacturer of the ink color difference meter is produced by Shenzhen Sanenshi Technology Co., Ltd., which is a trinity of R&D, production and sales in the domestic industry, which is currently licensed by the industry and commerce. The industry has previously obtained the national first-level measurement certification. The design, production and inspection of products are based on the relevant standards and national standards of the International Commission on Illumination CIE. Passed the National Metrology Center SCM measurement certification (part), CE certification, ISO9001 international quality management certification, RoHS certification, German TUV good manufacturer certification.

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