Why coated proofing paper jams

This question does not seem to be explained. Everyone knows it. But I know that hundreds of export companies and proofing companies do not know how many times to explain to different customers each year. In the end, the customer was finally persuaded, but there was always something in his heart. "Why is it so bad?"

To answer this question, we look at two important parameters of paper.

First, whiteness: Whiteness is an important indicator of correct color. In color reproduction, the whiteness of paper has a close relationship with the vividness of the reproduction color. White paper with high whiteness can make the contrast in the color layers of the reproduction open, and the higher the whiteness, the greater the contrast of the printed matter and the increase in the reproduction of the reproduction product. The highest value of the density of the imported coated paper is good, and the whiteness is good. The longest reproduction curve.

Paper printed with color images does not actually print the surface whiteness of paper blanks printed on the Internet or graphics, except for the fact that the dots of different colors form the visual colors of the people through the additive or subtractive method. This space is mixed. With gray paper, it is as if a small amount of achromatic color is added to the various inks, which reduces the original saturation of the ink and thus shows a dark turbid color.

Second, the smoothness: the smoothness of the paper is also an important factor in determining the quality of the print reproduction. For offset printing, the paper with high smoothness can contact the blanket with the largest contact area during embossing, and the transfer of the ink is completed evenly and completely, so that the dots are clearly and fully reproduced on the paper, and the ink color is fully expressed. And gloss. Therefore, the smoothness of the paper is high, the field density value is relatively high, the dot enlargement value is relatively small, the ink film flow is dry, the conjunctiva layer is flat, and it is easy to form a mirror reflection effect, so that the footprint is glossy, colorful, and the smoothness of the paper is low The surface is rough and uneven. After the ink flows dry, the conjunctiva layer is uneven and diffuse reflection occurs, which makes the outlets of printing products empty, and the layers are reduced. The color is dull, and the ideal reproduction effect is not obtained.

As a paper jam, both whiteness and smoothness are significantly different from coated paper. With the same set of film, proofing with cardboard would not achieve the effect of proofing copperplate paper anyway. Our expectations are not too high and reasonable.

Source: "Packaging, Design, Printing"