What Is Prepress Proofing

Prepress proofing is an important link in the printing process, which refers to the process of copying various proofreading proofs from prepress graphic information through certain methods before the printing work officially starts. In short, it is to print a sample before printing, so as to test the effect. This process is an important step between prepress production and printing. It is not only the visual effect reproduction of prepress design, but also the basis of batch printing reference. 

Purpose of prepress proofing

Quality control: prepress proofing is an important basis for quality control after printing. Through proofing, we can check the quality of prepress production and provide characteristic parameters for prepress process.

Customer communication: the sample can be used as a communication tool with customers to help customers understand the final effect of the printed matter so that they can modify it in time.

Printing guidance: the proofing draft is the guidance of the printer for printing to ensure that the color, layout and other effects of batch printing are consistent with the proofing draft.

Prepress proofing method

Soft proofing: proofing with computer screen display is mainly used to preliminarily check the design effect, but the color reduction may not be as good as the actual printing. In fact, it is equivalent to the simulation display to achieve the effect of printing output, but after all, it is not a physical sample, which will be different from the subsequent printed products. This method is simple and fast.

Traditional proofing: also known as mechanical proofing, its printing method is basically the same as the actual printing. Copy the four-color screen to the PS plate, select the final printed paper type, modulate the ink, and print the finished pattern through the printing machine or the printing proofing machine. The quality of this method is high, but the cost is relatively high. Because it involves professional process steps such as plate making, startup and color matching. Mass printing will bring scale effect, and the cost can be greatly reduced.

Digital proofing: the use of digital printing machines for proofing, without the need for plate making, has the advantages of high speed, low investment and low cost. The process of digital proofing is controlled by computer with few human factors. Due to the differences in printing principles between digital printing and offset printing, the color presentation of digital proofing may be different from the actual printed products. But now the technology of digital printing is becoming more and more mature. Although the printing effect is different from offset printing, it is more efficient and fast. For small batch production, if digital printing is used for prepress proofing and subsequent production, the consistency between the sample and the finished product is effectively guaranteed. Of course, the proofing link also needs to carefully adjust the parameter curve.

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Precautions for prepress proofing

Color control: color is one of the most difficult factors to control in proofing. Different substrate materials, ink and dot gain rate will cause the change of sample color. Therefore, it is necessary to strictly control the color in the proofing process to ensure consistency with the final printed matter.

Proofreading of samples: after proofing, the samples need to be carefully proofread, including gradation, color, text, layout size, etc. The batch printing can be carried out only after it is confirmed to be correct and submitted to the customer for confirmation.

Proofing time: the contract sample should be printed shortly before printing to avoid fading and distortion of the sample due to long storage time.

To sum up, prepress proofing is an indispensable part of the printing process. Through proofing, we can ensure that the quality of printed matter meets customer requirements and avoid problems in the subsequent printing process. At the same time, proofing is also an important tool for communication with customers, which helps customers understand the final effect of printed matter.