What is the function of prepress proofing
in book printing process? Prepress proofing is an important basis for
quality control of printed matter, and it is also a tool for communication with
customers. We can print out the samples first and produce them in batch if we
want to do what we want, what we want, and if we are not satisfied.
Firstly, proofs can help users to check all
kinds of information contained in documents, so as to modify them in time, such
as font, image, color and page settings. Color is the most difficult to control
in proofing of book printing process, because different substrate
materials, inks and dot gain rate will cause color changes of proofs.
Secondly, proofs can be used as contracts
between customers and printers. The color of the contract sample sheet shall be
exactly the same as that of the final printed matter, and it is better to print
the contract sample sheet shortly before printing, so as to avoid color fading
and distortion caused by long storage time.
Proofing is a process connecting prepress
production and printing, which allows users to foresee the final printing
effect before printing. At present, there are three common proofing methods in
gravure printing industry: soft proofing, traditional proofing and digital
proofing in book printing process.
1. Soft proofing
Soft proofing is realized on color display,
which is undoubtedly the most convenient, fastest and cheapest proofing method.
It requires high precision of color display and must be calibrated correctly.
The obvious shortcomings of soft proofing are: low resolution, only 72dpi;
color accuracy depends on the performance and calibration of the display; can
not provide a reference hard copy for the subsequent printing process.
2. Traditional proofing
There are two kinds of traditional gravure
proofing methods, one is gravure proofing, the color of the sample is accurate,
high reference, but this proofing method needs to go through grinding, electric
carving, electroplating and other processes of book printing, which
requires high accuracy of plate cylinder processing, high electroplating cost
and complex process, so 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, need to
output film and print, and then in the offset proofing machine to complete
proofing. Although this method can reduce part of the production cost, but due
to the offset and gravure printing process is different, proofing effect is
quite different, the true density is insufficient, color level is equal.
