Color printing is the reproduction of images or words in color (corresponding to black-and-white printing, or monochrome printing). It includes many steps, or conversion process, in order to produce high-quality color copies. The following are some main steps of color printing and some historical evolution.Analysis of Color Printing
The color separation process is used to digitally scan the original and divide the original into red, green and blue components. Before the development of digital imaging, the traditional method of color separation was to take pictures of the image three times, each time filtering different light with a color filter of the corresponding color. However, after color separation, the required result is three gray images, which represent the red, green and blue components of the original.Analysis of Color Printing
The next step is to convert each color splitter. When generating a negative image of a red component, the generated image represents the component of the image. Analysis of Color Printing
Similarly, negative pictures of green and blue components are also generated to produce red and yellow color separations of the finished product accordingly.Analysis of Color Printing
Cyan, magenta and yellow are subtractive primary colors, because each color represents the remaining two additive primary colors after subtracting one additive primary color from white light. Cyan, magenta and yellow are the three main pigments in color reproduction.Analysis of Color Printing
When these three colors are combined in printing, the original can be reasonably copied, but this is not the case in practice. Due to the limitation of ink and pigment, the darker color is dirty and dirty.Analysis of Color Printing
In order to solve this problem, we need to make a black version to improve the color of the dark part and improve the contrast of the image. There are many technologies to make this black plate from the original image; These technologies include gray component replacement, background color removal and background color increase.Analysis of Color Printing
Printing inks cannot be mixed. For this reason, only one color of ink can be printed at a certain position on the paper at a time. The visual mixing of different colors printed close to each other gives the viewer the concept of continuously adjusting the image. Analysis of Color Printing
To separate the colors from each other, you can use the screen to achieve this purpose. The generated dots are also called halftone or mesh tone.Analysis of Color Printing
The traditional halftone screen is made of two glass plates. Each glass plate has lines filled with ink, and the two glass plates are bonded vertically. Through these screen exposure, each color dichroic film is made.Analysis of Color Printing
Once an image with high contrast is developed, dots with different diameters are formed according to the amount of light received in the area, and a gray color separation image is prepared.Analysis of Color Printing
The glass screen is gradually eliminated after the emergence of high contrast film, which is a halftone screen made by color separation film exposure. Then it is replaced by the process of generating halftone on film directly by electron with laser. Analysis of Color Printing
At present, computer direct plate making (CTP) technology can make the printing factory completely avoid the film part of this process. Analysis of Color Printing
Computer direct plate making technology directly images the dot on the printing plate with laser, which saves cost, improves quality (because it reduces repeated replication), reduces production time, and reduces the harm of toxic film processing chemicals to the environment.Analysis of Color Printing
60 to 120 wires per inch (LPI) the screen of the screen cable is used to reproduce the color image on the newspaper. This cannot achieve high-quality reproduction, but it is already the best screen tone that can be achieved by cheap absorbent paper. Analysis of Color Printing
Finer dots will spread the ink and stain the color. The best way to see the screen tone is to check the image of the color newspaper with a magnifying glass. The screen of 133 to 175 lines / inch is used for Magazine printing and commercial printing.Analysis of Color Printing
A measure of how much paper is absorbed or spread is called dot gain.
FM screening
Digital screening technology also makes screening technology reach a new level. The most famous is FM screening. Because the dot of this screening method is random, the moire effect produced by the traditional mesh adjustment does not exist. Another advantage of FM screening is that it can get a wider color gamut when using the same ink.Analysis of Color Printing
Almost all inkjet printer devices use FM screening. If you have an inkjet printer at home, you can take a magnifying glass to see the image you print.Analysis of Color Printing
FM screening or some traditional screen line screening and FM screening have gradually become the standard screening method of offset printing or lithography.Analysis of Color Printing