Printing with spot color should pay attention to the white

With the development, four-color printing can no longer meet the color requirements of exquisite products in some aspects, and the application of multi-color printing is gradually becoming more and more extensive. In the desktop plate making technology (CTF) process we are familiar with, multi-color printing can use film, printing, and proofing to check whether the ink color matching, spot color ink and four-color ink The edge overlap of the adjacent area is reasonable, because the cost is very low, it can be By modifying documents and film proofing, repeated experiments until the customer is satisfied before printing.

In the computer-to-plate process, what we see before publishing is a digital sample, which will never have color leakage or heavy color phenomenon, but when it is printed, even if the CTP version is produced, errors are inevitable. This error is only In the process of making documents, make up for it by trapping (Trapmg) on ​​the documents, embossing or removing according to different situations. Therefore, in the CTP process, the prepress treatment of spot colors is particularly important.

Generally speaking, if the spot color ink is different in depth, the size of the trap will be different; if the spot color and the four-color color match are different, the trapping method will be different.

1. The dark spot color is connected to the light color, and the light color is trapping to the dark color. The value is generally between 0.02-0.15mm.

2. When the dark spot color is connected with the darker four colors, trapping should generally be done from small to large areas, and the value is generally 0.05-0.15mm. In PackEdge software, 0.05-0.15mm after trapping is automatically Embossed. The principle is the same in CoreIDraw, but the processing method is different, which is more troublesome.

3. For colored text on spot colors, no matter how the color is matched, the text should be used to trap the background color, so as to ensure that the text shape remains unchanged. In CorelDraw, convert the text into a graph and process it as a graphic. In the four-color layer, fill the borders of the same color according to the size of the text to achieve the leak-trapping effect.

In CorelDraw and Photoshop, the raster image processing spot color can be layered or divided into multiple channels, but in PackEdge, because it receives PS, EPS, TIFF, PDF format files, it can directly process vector graphics and text Do Trapping, but the spot color effect of the image will change, let alone Trapping, you can only select the masks of different images to refill the spot color. For images with effects, such as blur, transition, and feathering, you need to use PackEdge Medium rework, its effect is more natural than CorelDraw and Photoshop, the transition steps are much smaller, and the color uniformity is the obvious advantage of PackEdge's transition.