Four colors or more special color reproduction techniques and performance

Before the “Spectral Separation Method” formed four-color Process Color printing, most of the color printing was done by hand, including the color printing and printing of dozens to hundreds of editions of Chinese Woodcut “watermark watermarks”, which formed a very realistic The picture and the original painting can be confusing. Japan’s ukiyoe prints and jin dynasty paintings use this style of painting and printing methods to add a lot of interest to the art of Japanese people’s life. The watermarks of the woodcuts on the tombs of the Tokaido 53 times show a lot of local customs, and it deeply affects Later European Impressionist style. When lithographic technology was introduced to Japan, some artists with high artistic accomplishment switched to using "lithographs on color" to express shading and texture with point-spotting or open-color cymbals. As long as ten or twenty colors can be printed, they can form very beautiful lithographs. The effect, purely based on the experience and judgment of the colorists, was printed using Western stone printing inks, setting a very exquisite work for the painting.

Invented photography in the 19th century, and developed the "black and white photo coloring technique", so in the beginning of the 21st century, it used the four-color printing of letterpress to add and subtract color with carbon powder drawing techniques on continuous glass plates, such as green leaves plus YC printing plate, minus M The version can be green, the brick wall plus YM, the C version can be reddish-brown, and the like, the color of the editor's common sense is used to open the color, and the net western version is eroded to form a nearly manual coloring four-color relief original color version. Postcards, such technologies represented landscapes and architectural images in the early days of Japan, in Manchuria, and in Japan.

The other category is based on photographs or watercolors. It also uses lithography to red, yellow, blue, green, gray, black and other colors, full version, dot, dot or line, to complete the trapping, with photos or The image of paintings is a technique that inherits Jinhua and Ukiyoe in Japan. Taiwanese painter Mr. Lan Yinding also worked on the cover of the book. Qiuyu printed the chairman of Lin Qiuyu. In the early years, he also created his own trademark and propaganda. Advertising color printing works.

These techniques were still used during the 1950s and 1960s. After the 1960s, when Taiwan’s photography became popular with four colors, the technique of manual color registration was only gradually declining. Everyone changed to color separation, over-netting, and four-color gravure printing. Become a formal technology, then directly through the network separation, electronic scanning color separation, grouping system, to today's color EPS system, printing using four-color mesh CMYK four-color overprint has become an unbreakable model.

Why do I need special color printing? Because there are several defects in the four-color color printing, we must seek a better way of expression. What is wrong with the four-color printing method? The first is the ink concentration, only about 1.6, compared to the photo 2.0 concentration, slide 2.8 concentration, there is a distance. The second is the performance of outlets. The outlets in the optical department are small and there is no thick separation. The third is the lack of ink color saturation, turbidity is too high, can not show thick and bright colors, so that some secondary colors appear dirty. The fourth is fluorescent, metal, and other special performance.

How to make up for the lack of four-color printing

Based on the above reasons, special colors with different methods can make up for four-color printing defects:

(1) Insufficient ink printing density, in addition to four colors, plus secondary colors such as RGV (Blue) three colors, so that the secondary color has a concentration of about 2.0 to 2.2, so how to do a good job outside the four-color RGV special The color version, which has the effect of increasing the concentration in the overlap, does not produce the wrong phenomenon of mis-network and color interference, and is an important direction in the work.

(II) The performance of the optical department to the intermediate tone network is not as strong as that of the printed version. It can be replaced with the ultra-fine 300 lines and 400 lines with the Internet. However, it is found that the ultra-fine network line is not well printed, resulting in a complete The color of the print is not good, so it is changed to a four-color printing, and the percentage of dots in the light part is reduced slightly. The light feel of LC light blue, LM light magenta, etc. is used to compensate the light part. Some use LB(G) gray light gray, LR light Peach, LG light green, LV light purple and other secondary light color for this, this is a kind of hand-colored lithography extended technology, how to make up the complementary color concentration and subtract the original four-color version of the dot percentage is open The most difficult and necessary considerations for technicians are original and supplemental enhancements. As for the use of dark colors in the dark areas, it can be slightly less than the concentration, but only increase the concentration of about 0.1. Is it worthwhile to do it?

(3) Insufficient ink chroma, most of which occur in the quadratic color RGB place, so Pantone has a special orange and green special color increase method, including the plate making software program, and the specified ink color, to become a complete set to increase the chroma Program. Use software (such as Photoshop) to replace RGB in four-color version of RGB, full replacement 100% take away, 100% change the second color is not ideal, 20/80, 50/50, or other 40/80 ratio, To overfill and increase color and other techniques, it is a matter of looking at the colorists.

(D) The performance of fluorescent color and metallic color is basically a reflection of the design will have a fluorescent color. The color is defined by the full or high percentage of dots. It is important to print the color before the four-color printing. How to print the opaque color before printing the four-color ink will not produce too much masking. As for the fact that special fluorescent colors and metallic colors are already outside the four-color or color reproduction field, close cooperation between the color maker and the printing conditions is essential.

Based on the above four techniques, some companies already have four-plus-two six-color and four-plus-three seven-color software. Many of the colors, proofing, and printing work still need to be considered together to achieve better performance. And light tone, even fluorescent and metallic color reproduction.