Three places book: how to meet customer requirements for printing color performance
We are a big printing company in Shenzhen China . We offer all book publications, hardcover book printing, papercover book printing, hardcover notebook, sprial book printing, saddle stiching book printing, booklet printing,packaging box, calendars, all kinds of PVC, product brochures, notes, Children's book, stickers, all kinds of special paper color printing products, game cardand so on.
For more information please visit
http://www.joyful-printing.com. ENG only
http://www.joyful-printing.net
http://www.joyful-printing.org
email: info@joyful-printing.net
Hong Kong
The author Zhong Jinrong entered the business in 1972. During the period, he participated in commercial photography, black room printing, special effects production, color separation plate making, book publishing, output center, Mac design and layout training, desktop publishing and prepress system planning. In recent years, he has focused on projects such as printing process and color management, and has also participated in the teaching of the printing skills improvement course.
The "Printing Arts Society Monthly" "Three Books and Calligraphy" was published in April 2005. Many senior industry leaders from China, Hong Kong and Taiwan exchanged information in the form of letters, so that we have more information on the printing industry in the three places. Understanding. The Honorary Chairman of the Honourable Yu Hung-kwan proposed to continue the "Three Books and Calligraphy" in another form. They exchanged ideas through interactive forms. Members of the industry were welcome to respond and participate in the discussion. In this issue, the author will discuss with you about the printing color performance. The topic.
The author's main job in recent years is to print color management consultants and teaching. The problem often encountered is "how to meet the customer's requirements for printing color performance", and this topic is borrowed as the beginning of this forum. The types of printing work are roughly divided into three main categories: book printing, packaging printing and paper product printing, but no matter which type of printing, it will face the problem of color performance. There are usually three aspects to the customer's performance requirements: (1) It is difficult for such customers to master his receipt standard by feeling of receipt. However, once it is mastered, it is easy to handle because there is no target for color. (2) Based on the physical color, this is a very reasonable method, but it can't be processed when some colors outside the printing gamut are encountered. (3) Checking the accepted proofs, which is the mode of work used in most industries, but pay attention to whether the color samples provided by customers are within the printable color range.
The performance of color is derived from the color characteristics of the material. If the color characteristics of the printed material are poor, the performance of the printing machine will not change its color performance. In the field of four-color printing, the ink is not pure enough, so some colors cannot be expressed. For example, orange is composed of magenta (domestic magenta) and yellow, because the composition of magenta ink has cyan, and cyan is orange. The complementary color of red, which neutralizes the orange, so that the orange does not reach the desired saturation. For example, blue is composed of magenta and cyan, because the composition of magenta ink has a large amount of yellow components, and yellow is the complementary color of blue, so that blue with high saturation cannot be printed.
Most printers encounter the inability to achieve the saturation of the customer's color sample. As mentioned above, the appropriate amount of saturated ink is usually mixed into the original four-color ink. The most common is pink. (For example, Pantone Rhod. Red) mixed with magenta to make the color have higher saturation, because pink has lower Gravness and Hua Error, especially when it is biased towards yellow. Improved, so the blue color printed in this combination will have a higher chroma.
This kind of processing is necessary to cope with a part of the color, but not comprehensive enough, so the high-fidelity color of the multi-color combination is also translated into the original color (Hi-Fi Color) came into being. In 2002, the Hong Kong Graphic Arts Society I have initiated a study on high-fidelity color printing. The author is the host of the research project, and there are more than ten participating institutions and printing houses. Finally, everyone has a better understanding of this technology. In recent years, customers have begun to understand what is the printing standard, such as ISO 12647-2, printing color characterization data such as FOGRA 27L, 39L, etc., and knows to require some programs such as G7 to achieve the specified printing level, etc., and also began to accept data printing. (Print to Number), virtual proof (Virtual Proofing) and other printing methods. Printing by data is achieved by the master according to the printing characteristics data specified by the guest, such as solid density, dot gain and gray balance, without completely aligning the color of the reference color. The virtual draft is that there is no color sample printed on the physical material. Instead, the printed pattern is displayed on the screen by means of color management. The printing master looks at the screen color, when the print color is visually displayed on the screen. The colors are close to each other and can be delivered.
Because there are so many factors that affect the performance of printed colors, and different customers have different requirements, is the use of mixed inks or high-fidelity colors with multi-color combinations? Is the traditional ink wet draft still using the increasingly popular digital draft? Whether the color samples from customers are suitable for printing, or even whether the files from the customers have suitable color separation settings and processing, this pile of questions is just to discuss with you through this forum.
Taiwan
The author Chen Zhengxiong was engaged in the zinc letterpress process in 1958, and was skilled in color image work. In 1976, he founded the "Printer" magazine with his brother, and was the CEO of the Taipei International Printing Machinery Exhibition and the publisher of the "Printer" magazine.
First, the traditional process of printing color reproduction management
The color management that must be done in the so-called traditional printing process does not have to use new wide color gamut inks, new six-color, seven-color or special color printing. Instead, it is segmented to do digital color feature management control. In the image input, including the scanner, digital camera, etc., IT/7-1 or 7-2 is used as the input condition of the transmission and reflection drafts. The color correction of the instrument can achieve the correct image color and be converted into the correct one. RGB image file. Secondly, a mid-screen color correction is established, and the sensor is hung on the screen for measurement, and the color management program is started to make the illumination color reproduction of the screen conform to the prescribed number, but also pay attention to the interference control of the background light. If the same screen color correction, such as X-Rite system calibration, is done in the production factory, remote production equipment screen, customer proofreading screen, then you can do long-distance soft proofing, which can be seen on the pre-press screen. The same color image is presented, doing the same color output certification job.
The output equipment includes digital printing, lithographic printing, pre-press proofing and other stages and methods of output. Today, digital printing, especially inkjet printing, its color density and color gamut range have exceeded the lithography. Using the new generation of IT8/7-4 color management system, more than 1500 color grids for more accurate color management, color density and chroma gamut performance can fully meet customer needs, except gold, silver and fluorescent colors. Therefore, once a color correction can be done every day, it is necessary to pay attention to the changes and responses of different printing media. The lithographic proofing is a print made before lithography, and the color correction of IT8/7-4 must conform to the realistic color reproduction specifications of lithographic printing, including the use of PS or CTP, the conditions of the printing press, and the printing production conditions. , ink conditions, media paper conditions, that is, changing machines, different inks, different papers to different temperature and humidity and pressure conditions, must print different colors of IT8/7-4, and then give back to the proof output The color correction, only in this way, can print a variety of sample colors that meet the customer's approval, otherwise the proof will be like a wild horse. In the case of color density and gamut, the listed samples will be signed by the customer. If the printing press is not printed, it will not be able to produce smoothly. The stability of the color of the whole batch of prints depends on precise ink discharge, printing machine water supply, ink supply temperature, humidity stability, off-line measurement, and connection measurement, such as measurement on Roland Eaqle Eve machine, to achieve accurate color and control objectives. Keep the front-end to color conversion RGB to CMYK correct color gamut compression, CTF plus print version, CTP publishing stability, printing material and printing conditions stability, often do color management features file re-editing, then there is a stable traditional printing color performance The best pillar of the series.
Second, the wide color gamut needs and performance
(1) Use the FM frequency network 300 lines or finer network cable to make the halftone printing of the dots close to the continuous softening performance of the photos. (2) Using the new nano CMYK ink, the printing density can be increased by 0.2 or more, such as the original 1.4, 1.5 full version density becomes 1.6, 1.7 or more, while the magenta and blue color rendering is better, making orange Red, pink, purple, indigo to green for more brilliant and pure colors, especially red purple, purple, indigo. (3) Use CMYK plus O+G or O+V two special colors, even CMYK+RGB seven-color printing, making the color gamut more widely, red, purple and green more pure, to meet the new generation of computers, TV screens The user is dissatisfied with the chromaticity and color reproduction density of the printed CMYK conventional ink. (4) Use Lc light blue, Lm reddish to increase the solid sense of the light color below 25% of the dot: unlike the dot-sparing performance. In the inkjet at 720 dpi plus Lc, Lm has 1440dpi performance.
Third, cost and technology will lead the change
Using nano pigment inks, more color, good media, higher cost, can customers accept? Where is the market? Like the Océ C-900 toner printing machine, it uses CMYK+RGB seven-color toner to express, the effect is good, the speed is slow, and the development of hardware and software is more expensive. Is there a market? Still waiting for time to prove.