Four-color printing ink use 诀窍 (a)

In color printing (four-color printing), it is difficult to obtain ideal blue, purple, and green colors due to impure ink (mainly cyan ink). Also, the amount of ink is limited in printing. For example, if you want to print black pages, you may think that: CMYK is printed at 100%, and it must be very good. However, the answer is: wrong! Four 100% color plates are printed, the paper can not stand, the ink does not dry properly, the paper will stick together, or the ink will spill out of the roller, resulting in not only not ideal black, but a blemish. In terms of experience, the total amount of four-color ink should be less than 300 unless you have close cooperation with the output and printing departments. Do not believe? Well, open Photoshop, ask for a New file, convert it to CMYK format, and fill in the darkest black. In short, do your best! Then, open the info display board, put the mouse on the screen, look at the CMYK display of info, add these four percentages, how much? 266! Far less than 300. You must pay attention to this point. Too many four-color totals are absolutely a bad thing. well, let's get back to business. Due to the restriction of the amount of ink, the ratio of black to other colors at the time of color separation is increased, and the image is not easy to be bright. How is it? (Since the total amount of ink is limited during printing, when black is added, the ratio of the other three colors must be reduced.)

The best course is of course to manage the black channel as much as possible. When converting an image into the CMYK color space, the precise creation of the black channel helps to better describe the details in areas where shadows and contrast change. Increasing the amount of detail and increasing the contrast can all enhance the color saturation of the image, which will make your eyes feel that the color of the image is brighter than the actual color.

We know that color separation with CMY tri-color inks will lack contrast and blurring, especially in tonal variation areas and dark areas. With the black channel, the image will appear clearer and the colors will be more vivid. Because black enhances the appearance of the outline effect, that is, played an emphasis on the picture.

However, simply adding black ink does not guarantee perfect color. For professionals, one must care about how much black is added, where they are added, and how to establish the best ink distribution balance between the channels. We have mentioned the term “separation parameter” in several articles. We will specifically explain it later. Please see the second article “Mastering the Black Channel—Separation Parameters”, but for now, please refer to the following section. After reading it, they are all related.

The total amount of black ink determines the total amount of black in the image relative to other three-color printing plates. For most types of images, it is more appropriate to set a light black, which is quite dark with the outlines referred to in conventional printing, ie using only the appropriate black to increase the profile and enhance the contrast and detail. If you need to increase the amount of black in the image during color correction, you can start by increasing the black level of the image. This helps maintain the clarity of the image.