Digital proofing and its application points

Proofing is the key link in prepress printing and printing in the current printing industry based on computer technology, network technology, new materials and complicated processes. It is an important means for quality control and management in printing production. It controls printing quality and reduces printing. Risk and cost are extremely important. With the digitization of content expression and process control, the product cycle is declining and the production efficiency has been rapidly increased. Therefore, the requirements for proofing technology for quality control and product inspection in the printing production process have become higher and higher, and new digital proofing products have to be shipped. Health, and began to provide relevant standards for printing, to provide users with quality standards or acceptance standards for printed products.

First, digital proofing and production processes

Digital proofing refers to a new type of proofing technology that directly outputs color proofs based on digital publishing and printing systems, and publishes graphic and textual information in accordance with published printing production standards and specifications. . It uses a large-format printer to directly output proofing digitally to replace the lengthy proofing procedures of traditional film making and printing. The digital proofing system is generally composed of a color inkjet printer or a color laser printer, and a color proof and an analog print proof color are used to obtain the proof proofs from the digitized originals (electronic documents).

1. Digital proofing system. The digital proofing system is based on digital publishing and printing system (CIP3/CIP4). It uses the same page graphic information (RIP data) to reproduce color graphic information from computers and related equipment and software, and controls the quality of the printing production process. At present, the digital proofing system consists of two parts, a digital proofing output device and a digital proofing software. It adopts digital color management and color control technology to achieve high fidelity in the same color gamut as digital color proofing. The digital proofing output device refers to any color printer capable of digital output. For example, a large-format color inkjet printer that is most commonly used at present and capable of satisfying the publishing and printing requirements is a digital proofing control software that is the core and key of the digital proofing system. , mainly including RIP, color management software, imposition software, complete the page digital screening, page combination, ink color gamut and print ink color gamut matching. At present, the most representative is the BlackMagic digital proofing system using the true dot technology.

2. Digital proofing process. Digital proofing process is: receiving page electronic file - RIP - digital proofing. Work processes include: System Settings - Electronic Document Acceptance - Imposition - Select Proofing Materials - Digital Proofing. Normally, a set of four-color digital proofing needs 15 to 30 minutes. A set of good digital proofing software can control multiple digital proofing machines, so the production efficiency is very high.

Digital proofing is not only different from traditional proofer circular flattening printing methods, but also different from the printing method of printing circular press circles. It is based on the color rendering range of printed materials and the same RIP data as the printed content, using color gamut. The large space color printing matches the printing method with a smaller color gamut space to reproduce the printing color, and can meet the requirements of various printing methods such as flat, concave, convex, soft, and net, and can produce proofs according to the user's actual printing conditions. It solves the problem that the proofing cannot be matched with the subsequent actual printing process, which brings difficulties to the printing.

3. The advantages and disadvantages of digital proofing. Compared with the traditional proofing, digital proofing has the following advantages: 1 The equipment investment is small, the floor is small, and the environmental requirements are low. 2 Save human resources, reduce costs, and rely on the experience of operators. 3 speed, stable quality, repeatability, low cost. 4 Wide adaptability, especially suitable for direct plate making, gravure printing, flexo printing and other processes that cannot be proofed or not easily proofed. It can not only simulate the effects of various printing methods, but also integrate with digital devices such as CTP (computer-to-plate) and digital printers to truly realize an automated workflow.

Currently, there are deficiencies in the applicability of digital proofing compared with traditional proofing: 1 Spot color proofing In addition to the few professional digital proofing systems such as Black-Magic, the digital proofing system supports spot colors, but it actually uses spot colors for CMYK. The four colors represent fixed spot colors, which are not exactly the same as the spot colors used in printing, and are similar to the spot colors used in printing. 2 Different network structures In addition to the high number of Black Magic and other digital proofing devices with real networks, the basic use of dye-sublimation or no-dot dye sublimation technology is completely different from that of traditional dot-mats used by printing operators. Printing operators need to For some time to adapt and accept the results of digital proofing.

Second, the application of digital proofing

At present, the digital proofing system has received eager attention from the publishing and printing industry. Its product quality, production efficiency and ease of use are loved by professionals in the industry, showing good development and application prospects. However, due to the fact that the basic and application targets of digital proofing technology are not completely the same as those of traditional proofing, it is necessary to pay attention to the following application points in order to accurately understand digital proofing:

1. Network structure. The dot pattern adopted by the digital proofing method is not exactly the same as the traditional printed dot pattern. It is difficult to detect the potential moire failure in screen printing. The printing personnel must use the tone matching control method to check the printing quality during the printing process, instead of the traditional one. The dot structure matching method.

2. Color control method. The digital proofing system is different from the conventional proofing in which color density is controlled by the density of the field and the dot value, and the color matching color control method is used to establish the consistency of the printing color gamut and the printing color gamut, that is, to establish the ICC Pro file. Ability to match different printing methods, different printed materials, and different production environments.

In short, digital proofing is an emerging technology and a key part of the digital production process of modern printing. In eliminating the influence of man-made and external factors, the stability of the proofing output is greatly improved, the proofing process is shortened, and the proofing cost is reduced. Digital proofing, as an important part of the digitization of the printing process, determines that the proofing of the future must use digital proofing technology and eliminate the traditional proofing, which has become an inevitable trend in the printing industry.