Pdf application skills - portable file format
a few years ago, according to the statistics of the American Printing Technology Foundation (GATF), 88% of the surveyed printing enterprises and prepress professionals encountered difficulties in dealing with PDF files submitted by customers, and the method was also incorrect. Among them, 46% of them had been trained in the practical operation of PDF, but there were still many problems. So far, there are still many printing houses that have obstacles in dealing with PDF files
1. Transparency: the end of the nightmare
for designers, "transparency" is a very useful tool, but many printing staff are very scratching their heads about documents with transparent layers. For this reason, rips (page description grid image processor) based on Adobe postscript 3 need to be improved to deal with the transparency problem. However, many rips used today have not been upgraded to this level
fortunately, acrobat 6 can merge transparency and print out files, otherwise it cannot be directly output to rip. When processing, don't be confused by the transparency flatter preview command under the Advanced menu. This dialog box is only used to preview the various effects of transparency on other objects in the file, and it doesn't have a real impact on the image. Transparency can be truly flattened only after the file is printed or saved in postscript file format
(1) open the "print" dialog box, click the "advanced" option to view the transparency flattening under the "advanced print setup" command
(2) when the slider is moved to the left of "raster", the transparency of all action areas will be flattened, and the vector object will be converted into a raster object
(3) change the default 300ppi "line and text" resolution to not less than 1200 PPI. If the film is output at 2400 DPI, the 1200 PPI setting has a good effect on low and medium resolution printing
2. Raster processing of vector image even if the barrel temperature is higher
before entering the production process to create PDF files, do not raster the vector graphics. Usually, people convert the vector files to JPEG format, so that when the file is converted again later, the quality of the file will be lost to a considerable extent. It is recommended to use the lossless JPEG 2000 format as the conversion format, It can minimize the information lost in image compression
3. PDF writer and distiller
acrobat versions before 6.0, PDF writer is the best choice to create PDF files. However, the setting of PDF writer is not suitable for prepress processing, and distiller is the best choice for PDF prepress application
after receiving the file, the most important work is to check the specific application of PDF file. The steps are as follows:
(1) open the file
(2) select the "file" menu in the menu bar
(3) select "text attribute"
(4) select "description" command
(5) in "PDF information", you can see the creator information of PDF file. If the creator is PDF writer, customers can re create PDF files through distiller to meet prepress needs
you can also change the pre check settings of PDF files through PDF writer or other available settings. 2. Directly click the Merlin icon on the computer desktop
4. Missing fonts
one of the common problems of PDF is missing fonts. If a certain font is not embedded in PDF, it will be replaced by Adobe sans or adobe serif, which cannot achieve the desired visual effect
the reasons why a font cannot be embedded in PDF are as follows:
(1) when postscript is created, the font cannot be activated in the local application
(2) in postscript settings, the font inclusion type is not set to "all"
(3) the setting of Distiller is incorrect
note: when distiller a postscript file, all fonts should also be embedded
pitstop professional edition can be selected to solve the problem of font loss:
(1) select the "selec object" tool
(2) select the "window" command, and then select "show pitstop inspector"
(3) select the "text" tab
(4) click the "font picker" button
(5) select the "page" tab, which will display the font used for a specific page, and the "document" tab will display the font used for the entire file, The "system" tab displays the fonts installed in the system
(6) use the "system" tab to display the system activated fonts, select the fonts you want to embed in PDF, and then select the "embedded font" check box
analysis of the composition and morphology of wear products particles (7) click "OK", Embedding fonts in
5. Color separation
color processing in printing color separation has always been a difficult problem, especially in software that does not support CMYK four colors, spot color and RGB files should be converted into corresponding CMYK files
if the typesetting software is used for printing color separation, the most ideal color separation program should be used for color conversion. Acrobat goes a step further in processing colors. It can not only complete color conversion in the "advanced print setup" dialog box, but also soft proofing colors through the display before printing. The steps are as follows:
(1) Select "advanced", then "separation preview", and the color separation preview dialog box will show the colors contained in the file. If the file contains a spot color, the color will be displayed together with the CMYK color
(2). When the cursor moves on the page, the ink percentage at the cursor position will appear on the information bar. At this time, you can select a specific color to modify and check the color mixing, which is very helpful for four-color printing with a two-color printer
6. Wrong color space
in printing applications, another frequently encountered PDF file problem is to convert images and text in CMYK mode into RGB color space files in PDF files. In pitstop professional edition, solve the problem of RGB image. The process is as follows:
(1) find the "selec objects" tool
(2) select "window", and then select "show pitstop inspector"
(3) select the "color" label
(4) click the "change into CMYK" button at the bottom of the dialog box. In the pitstop professional edition, the process of solving RGB problems is as follows:
(1) use the "selec objects" tool to select part or all of the RGB text
(2) select "window", and then select "show pitstop inspector"
(3) select the "color" label to confirm the text color space
(4) select "window", Then select "show pitstop global change"
(5) find the "object" label, and then select the "color" label
(6) select the "RGB range" button in the left column, and if necessary, specify the color gamut
(7) click the "CMYK range" button in the right column, Explain the color to be converted from RGB text
(8) in the lower left corner of the dialog box of "overall conversion", explain whether the conversion should be applied to the current page, a group of pages or the whole file
(9) click "apply 1. Adopt digital control system"