PRODUCTS CENTER

It is a subject worthy of close attention and serious consideration to extend the traditional four color printing to six color printing. The six color printing process is based on the traditional four color printing and is obtained by expanding the standard four color unit. But it is different from the hexagonal spot color process. The hexagonal spot color adds orange and green on the basis of CMYK, while the six color overprint here still contains only four CMYK colors.
Two new colors are not added to the six color system, but instead of standard cyan and magenta, their lighter and darker series are used respectively. CMYKLcLm is used to represent six color printing. Here, C and M represent dark cyan and dark magenta, while Lc and Lm represent the lighter colors of the two colors. There are also CMYKcm or CcMmYK.
Note that these names do not indicate the color order, they only indicate the hue of the colors used in printing. The use of two different ink densities is called two field or two color reproduction. It is a change of the new color reproduction method called "n channel", where n represents the number of colors used for printing.
There are several important advantages of using two-color extended overprint ink. The biggest advantage is that it greatly expands the range of color gamut. Epson and several other inkjet printers and ink manufacturers are using a process similar to this six color overprint to develop inkjet printers in order to obtain more realistic image colors. Ink jet printing has become a more common digital alternative to film processors. Using a lower grade ink jet printer can produce extraordinary results.
By adjusting the intensity and density of the colors used for printing, we can improve the appearance. The appearance effect is enhanced because the use of two colors reduces the contrast between colors. For example, when we have a very bright magenta, we print the upper details with darker magenta. Under the effect of bright magenta, it may lose darker points and enhance the image. This method of printing halftone points in details to achieve the overall image effect is obviously continuous in hue. POP display and other large design patterns used for close look can get better results from this method.
Using the six color process can not only improve the image definition and resolution, but also smooth the excessive tone. Some colors that are difficult to obtain, such as meat color, barbecue food, water color, sky color, chrome yellow and similar metal colors, can be obtained by adding light color tones in the two tone printing.
Two tone printing also reduces the texture appearance in overprint. On the one hand, it reduces halftone dot patterns, and on the other hand, it expands the range of colors that can be copied. With six color printing, the rough halftone will appear less rough. A 50 line/inch halftone looks like 100 lines/inch, and a 65 line/inch halftone looks like 120 lines/inch or better.
Printing with two tones of cyan and magenta also expands the dynamic range of the copied image. The dynamic range is the difference between the lightest and darkest areas. In short, it makes the dark tone darker and the light tone brighter.
Most prints have a maximum dynamic range of no less than 2.0. This standard is rarely met in screen printing, generally between 1.6 and 1.8. A dynamic range of 2.0 means that 1% of bright dots can be restored. The copied ink can absorb 99% of the light and only reflect 1% of the light (compared with 97.5% - 98.4% of screen printed black).
However, the dynamic light sensing range of the human eye can reach more than 4.0 (1/10000 light can be felt, or 99.99% black can be felt). This is why the details of dark tones can be seen in the visual world, but cannot be realized in printing. With the two tone color mode, we can increase the dynamic range of printing to 2.2 (99.4% black). It seems that this is not a big deal, but we can see that the black layer obtained is better than that obtained by four color overprint.
With two tone printing, we have broadened the range of highlights and dark tones. In the past, when printing lighter soft colors or darker colors, our process often lost part of the layers and had shorter steps. Due to its soft appearance, good depth of hierarchy and dark details, the two tone tone is relatively longer.
Taking advantage of the control advantages of two tone printing on highlight colors, we have achieved better control over previously uncontrollable highlight neutral colors, such as beige, sand, ice, crystal reflection, detergent, yellow brown, etc. These colors have very few third color components. Two tone printing allows us to use larger dots in these color areas. In this way, we can have greater control over the environment and physical variables, obtain more accurate color reproduction, and reduce the shortening of the visible color range.
You can also get benefits in the dark part. By using darker colors than the normal primary colors magenta and cyan, we can better control the third color that needs to enhance the surface color of dark areas. Its main advantage is that we do not need to use too much black to compensate for the lack of darkness. The use of less black ink in the third color component can maintain rich colors such as reddish brown, walnut, dark red, chestnut, dark green, indigo, etc. In the four color mode, the necessary additional black completely covers the tonal components of these colors, presenting a flat and black color.
The use of two tones can compensate for the difficulty in copying lighter and darker colors, and the color drift phenomenon is also well controlled. Color drift refers to the color characteristics that will change the appearance when the color tone becomes darker.
The swimming pool is an appropriate example of color drift. Although it is a fact that the water in the whole pool is the same, for the observer, the deep water is bluer than the shallow water, that is, the shallow water drifts to yellow. This phenomenon relates to the absorption and reflection of light, that is, shallow water and deep water have different absorption and reflection of light. In the same way, printing ink is the same, so there is also a phenomenon of color drift.
In the example, the problem of color reduction is involved. A certain wavelength of light is absorbed, and the reflected wavelength constitutes the color we feel. Light tones tend to yellow, while dark tones tend to blue.
The challenge in printing is that when we increase the ink color density (Dmax of the ink layer), the color tends to be blue. The higher the density, the darker the color, but it tends to shift away from the soft dark tone and drift to the obvious blue tone. On the contrary, if we reduce the color density of the ink, the yellow drift will not appear in the high profile parts. Reducing the color intensity will show up in the dark part, where the color is relatively flat and loses luster, with a certain yellow drift.