In general, there are many reasons for the chromatic aberration, the chromatic aberration caused by the darkness of the same color ink printing; the color difference caused by the color difference of the same color ink before and after the batch; the color difference of the different series of four-color printing ink; the rheological property of the ink is not adjusted well. The ink supply volume of the ink fountain is not adjusted well or the temperature of the ink is too large to change the thickness of the ink layer in the image portion; the color sequence is changed, especially the light color is changed to dark color, and the original dark color on the ink is not cleaned. and many more. There are two broad categories of expressions:
(1) Color difference on the same page: There are generally two cases.
A. Same direction (up and down) color difference: light before the front or light before the light
B. Axial (coming and going) color difference: dark left or right or dark in the middle and sides
(2) Cross-page (including front and back) color difference: usually there are three cases
A. Before the light and deep: the deeper the seal.
B. Before the dark and deep: the more the more printed.
C. Flickering: When the time is deep and light.
Whether the color difference occurs on the same page or across pages, partial or overall, it is expressed as a color difference exceeding the standard. For the above various situations, the influence of the ambient color should be eliminated under the condition of standard light source, and the color difference of the same color ink before and after the batch should be understood. Through the sampling, the inspection is carried out, and the measurement of the color measuring instrument is used to control the ink and water balance. Ink and water balance, the color difference is controlled within the allowable range of quality.