PDF files for book print production have been used for well over a decade. Desktop Publishing software has undergone many transformations and now provides numerous tools for creating text and component documents. Some are easy to use and some not so much. The good news is that the basic structure of a production PDF is basically the same in terms of what is required for offset printing. The PDF many of you send to your printer for offset printing can also be used for digital printing and eBook conversion. This makes your PDF file more valuable than ever. The following are basic guidelines and tips for a good offset print production PDF.
Fonts must be embedded in PDF files. Currently two types of fonts are used, unlike the early days of Desktop Publishing, they are cross-platform. The same font can be used on a Mac or a PC. OpenType (OT) fonts are the replacement for PostScript Type 1 (PS1) fonts. Unlike PS1 fonts, OT fonts are contained in a single file. True Type (TT) fonts work much better than the early days and many are free. Use caution when downloading and using these free fonts. Many cannot be embedded in PDF files because of licensing restrictions. Whether using free fonts or those you have purchased, read the licensing information carefully to ensure that embedding in PDF files is allowed.
Typically during the preflight process two types of images are checked for: one bit and eight bit. One bit images are line drawings and other images that are solid black. One bit images less than 600 dpi are considered low-resolution by Sheridan Books and are flagged (this may vary from printer to printer). Eight bit images are grayscale and color images—usually photographs—with tonal detail. Those less than 200 dpi are considered low-resolution by Sheridan Books and are flagged (again this may vary from printer to printer).
In many cases printers will prints images that fall below the recommended minimum with acceptable print reproduction and can discuss these exceptions with you. (Time Saving Tip: If your file contains low-resolution images and they are ok to print that way let your printer know when you submit your files).
Your files can print black only or in color. Color printing includes Cyan, Magenta, Yellow, Black (CMYK) and Pantone Matching System (PMS) colors. PMS colors are most commonly used for items such as logos to ensure that the color is exactly the same in each printing or for a color that cannot be created in CMYK. Often publishers will send in files that were created in Red, Green, Blue (RGB). RGB files must be converted to either black or CMYK for printing. Sometimes RGB results because layout programs, such as Microsoft Word, only produce files in RGB. To ensure the best results discuss the conversion of your files with your printer.
Following these simple tips when compiling your PDF files will help make the process flow a little easier. If you are ever in doubt, the best thing to do is call your printer and ask.