Three types of proofing before printing and their

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Three types of prepress proofing and their advantages and disadvantages

proofs are the weight basis of print quality control and a tool for communication with customers, and their functions are mainly reflected in the following two aspects

first, the sample can help users check all kinds of information contained in the document so that they can modify it in time, such as font, image, color and page setup. Color is the most difficult to control in proofing, because different substrate materials, inks and dot gain rates will cause changes in the color of the sample

second, the sample can be used as a contract between the customer and the printing factory. The contract sample shall be accurately provided with the same color as the final print, and it is best to print the contract sample shortly before printing, so as to avoid fading and distortion of the sample due to long storage time

proofing is a process connecting prepress production and printing, which allows users to predict the final print effect before printing. At present, there are three kinds of proofing methods commonly used in gravure printing industry: soft proofing, traditional proofing and digital proofing

1. soft proofing

soft proofing is realized on the color display. It is undoubtedly the most convenient, fastest and cheapest proofing method. It requires that the accuracy of the color display should be high and must be calibrated correctly. The obvious shortcomings of soft proofing are: low resolution, only 72dpi; The accuracy of color depends less on the performance and calibration of the display than on the repeatability of the test; It cannot provide reference hard copy for the subsequent printing process

2. Traditional proofing

there are two common traditional gravure proofing methods. One is gravure proofing, which has accurate color and high reference. However, this proofing method requires grinding, engraving, electroplating and other processes, which requires high processing accuracy of the plate cylinder, high electroplating cost and complex process. Therefore, the production cost of this proofing method is very high, the cycle is relatively long, and it takes at least one day

another method is offset proofing, which requires outputting film and printing with ordinary computer, and then proofing is completed on the offset proofing machine. Although this method can reduce part of the production cost, due to the difference between offset printing and gravure printing process, the main switch is powered on, and there are great differences in proofing effect, such as insufficient density and equal color levels. The advantages of traditional proofing mainly include the following points

(1) the production process of proofing plate and printing plate is relatively similar

(2) proofing and printing use the same raster data. Potential problems, such as moire, layout and font, can be found through proofing

(3) when proofing spot color and metal color, the basic properties, limitations and failure modes of pits must be understood, and the printing ink and ink opacity perform well

the disadvantages of traditional proofing mainly include the following points

(1) high technical content requires professional technicians to obtain accurate samples, and labor intensity is large

(2) higher investment is required

(3) there are many processes involved, the cost is high, and the treatment cycle is also long

3. digital proofing

digital proofing technology is completely controlled by digitization, which changes the previous complex printing production process and reduces the cost at the same time. And the stability of plate making and printing quality is greatly improved. In gravure plate making, which does not need to use film, digital proofing is a more appropriate proofing method

the digital proofing technology is very mature and can fully meet the needs of gravure plate making. The design elements in gravure plate making are mostly graphics and images, and more spot colors are used, which mainly lies in that the colors shown by spot colors are more uniform and gorgeous than multi-color overprint, and have good stability. The use of spot colors in anti white graphics or text can reduce the difficulty of registration. Therefore, it is the key to evaluate the advantages and disadvantages of gravure digital proofing and test the accuracy of spot color restoration by proofing system. In addition to meeting the general four-color proofing, the support ability for spot color is also becoming more and more perfect. For example, the professional digital proofing system can provide a good solution to the problems often encountered in gravure printing processes, such as spot color overprint and trapping, spot color transparency control, spot color level transition and so on

the advantages of digital proofing mainly include the following points:

(1) there is no need to output film or make plate cylinder, which can shorten the production cycle and reduce the cost at the same time

(2) the quality of samples made based on inkjet technology is usually more stable

(3) digital proofing is an important part of digital printing. Its unique stability can provide standards for the whole printing process and provide a strong guarantee for the improvement of printing quality

the main disadvantages of digital proofing are the following:

(1) some digital proofing systems cannot ensure the integrity of document data

(2) the digital proofing system with the function of processing eye adjustment requires a higher cost

(3) spot color and metallic color cannot be reproduced accurately, and a specific system must be used

undoubtedly, with the continuous development and improvement of color management technology, digital proofing will show greater advantages in the printing process and occupy a dominant position

source: Advertising Technology Information

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