Prepress production and output of common problems

In recent years, prepress production software has become more and more diverse, and PC platform software has required more and more output. For some reason, the complexity of creating files across platforms and multiple software fusions has caused problems such as these. How to correctly produce and output the desired effect has become a matter of great concern to people. Through many years of production and output practices, the author proposes the following points of experience for reference.

First, about graphics, graphics software

The image processing software is mainly Photoshop. The problem that Photoshop needs to pay attention to is that the resolution of the image should meet the printing requirement of 300 or 350 dpi color mode. The general application of CMYK can make the output color consistent with the production time. If other modes are used, there may be a large difference between the output result and the production color. This is mainly because the general RIP will automatically convert the mode to CMYK, causing color deviation. The storage format generally uses TIFF, which is generally accepted by the production software, and the bottom-end image can be stored in the clip path. Larger files are best stored with color separation EPSs to avoid the appearance of image distortion in some composite software (such as PageMaker), and secondly, to speed up the process of forming PS files and RIP interpretation.

The vector graphics processing software is mainly Illustrator. Illustrator is very convenient and excellent in graphics production. The file format EPS is also accepted by all kinds of groupware, and stretch scaling does not affect the output. The main concern is that its 100% black is not automatically overprinted, but let empty. You can select overprint strokes or fills in the Properties window in the Filters - Colors - Black Overprint feature to select overprint strokes or fills. This will allow you to overprint any color and bring great convenience to spot color output. In addition Illustrator fonts can also be converted to path output, there is no problem using any beautiful font.

Second, on the version software

The common version software for Apple and PC platforms is PageMaker. The software is mature, but there are still some issues that need attention. The main advantage of PageMaker is that multi-page production and multi-point positioning are more convenient. The disadvantage is that the page size is limited and the font cannot be used at will, especially Chinese fonts. If bitmap download is used, the phenomenon of running and missing characters will appear. English fonts Downloading will not cause problems. The solution is to convert the word into a path in the graphics software and store it as an EPS before placing it in PageMaker. PageMaker can do spot colors and overprints by selecting a special color (spot color) in the defined color and checking the overprint option. PageMaker should pay attention to its own font effects (such as bold, double-image, underline, etc.). When outputting, there may be problems such as ghosting or invalid effects. These font effects are best produced in other software.

Third, on the Office software

Office, Word, Excel, Powerpoint, etc. are not software designed for printing, but office software, so it is more troublesome to deal with. The first is that the file cannot be separated by RIP, causing great inconvenience to color printing. The general processing method is to transfer the text to txt, and the picture is exported to TIFF or EPS, converted into CMYK, and then re-grouped and output in the groupware. If the black-and-white file output can be directly used to form the PS file with the original file, but it should be noted that the original file can not be brought directly to the output center for output. Different software environments do not cause a large change in the layout. Creating a PS file on the production machine and then explaining it to the output center RIP will not cause the issue of layout moves.

Fourth, on the CorelDraw software

At present, CorelDraw for PC platforms is widely used. CorelDraw is powerful, capable of producing vector graphics and groupings, and has many special effects. It is worth noting that the output gray is sometimes empty and sometimes not empty. In addition to 100% black printing, all grays are generally required to be empty. This requires the overprinting of the black hook on the color separation menu of the printing options. Make 100% black overprint, leaving the rest gray. There are cases where RIP cannot be interpreted in CorelDraw. The main reason is that there are too many curves or some wrong implied characters. At this time, you need to use the queuing method to identify this error and correct it. In the end, there is no way to test it and export it to AI and export it to EPS in Illustrator, or save it to other versions (such as CorelDraw6.0). The most stable) to output, as long as there is no special version of the special effects, generally work. CorelDraw has a wide range of importable image types, but it often causes problems. For example, when a PSD image goes to the background, it often happens that the image is damaged when the image is rotated, so that the image must be rotated and placed in Photoshop. Some types of pictures or special effects if the output finds problems can be converted to bitmap CMYK in the bitmap menu - conversion bitmap can solve the problem.

Fifth, on Autocad and other software

At present, engineering map software such as Autocad, Mapcad, MapGIS requires a lot of printing, but RIP software cannot output CAD files directly and needs to be converted. Generally, Autocad files can be printed and generated by PS printer to generate EPS files, then RGB colors can be converted into CMYK colors in Illustrator for output, and application software can also be programmed to color-combine and convert spot colors of RGB-colored EPS files. The thin lines are filled with real-color spot colors and then toned in printing, avoiding the problem of difficulty in aligning the color lines.

Sixth, on the application of RIP software

RIP software can be used not only to interpret PS files, but some application functions can also play some unexpected functions. For example, Harlequin RIP can output the PS file as a composite color TIFF or color separation TIFF file, so that the whole layout in PageMaker and other groupware software can be output as a TIFF or FPG for users to proof or electronic network version. RIP can also generally perform backend color separation if the picture in the file must be in EPS format. The back-end color separation can choose automatic 100% black to overprint and change the angle of any color version, and it is very effective in CAD output.

The major problems that arise in the production of output are file formats, fonts, black overprints, spot colors, layout moves, or color modes. I believe that with the above experience and principles, you can easily and freely output more software. Realize what you see is what you get.

Reprinted from: the printing of magazines: Lu Jian