Quantitative evaluation refers to the use of equipment and equipment to reflect the quality with regular test data, which can be roughly divided into the following categories.
1.Determination of optical density value The quantitative standard optical density is affected by both the ink layer thickness and the ink concentration. Using optical instruments (such as a density meter, etc.) to measure the data of the solid density of the ink, you can find the correct relationship between the ink supply and the dot area. Using optical reflection densitometer to identify the quality of printing can achieve the following purposes:

Control and check the thickness and uniformity of the ink, check the amount of ink in the length and width of the printed sheet;

In the formal printing process, check the ink volume of each batch of products;

Control whether it is relatively stable within the required range through measurement, so that the proofs and prints can meet the requirements of the original in terms of tone level, etc.;

Keep the dots clean and layer clear, measure the solid density value of the ink, control the dot changes and make it within the allowable value range.

2.Quantitative standard for determination of color value
That is, under the condition of a certain thickness of the ink layer, the hue, saturation and density of the ink are measured, and the technical indicators of the ink are checked. The chromaticity value can be measured with a spectrophotometer. Through the measurement of chromaticity value, the following purposes can be achieved. Through the determination of hue, the spectrophotometric curve of the three primary colors ink is measured and compared with the standard curve, the allowable deviation of the color value is obtained, the hue of the ink used is controlled, and accurate data is provided for the evaluation of product quality; ink saturation The purpose of the measurement is to control the color balance of the three primary colors, keep the ink color bright and pure, and do not produce old, pale and dark sense.

3.Determination of contour definition Quantitative standard contour definition refers to the physical form that dots, text, lines, etc. should be printed on paper. Because these physical forms are affected by paper surface properties, ink layer thickness, printing pressure and rolling forms, and printing materials and blankets during the ink transfer process during printing, form deviations occur. Through the definition of contour definition, the change value is controlled within the allowable error range to make it meet the quality requirements and standards. For example, check and control the standard thickness of the lines to keep the text strokes beautiful and strong. Use data to check and control the shape of the strokes and strokes of the text to achieve the specified quality indicators; keep the dots clear and round, check and control the dots on the paper Some irregular shapes appear.