What exactly makes a “print quality” PDF? As it relates to print production and your printed piece, a quality PDF contains all of the necessary items to print a job successfully on press, giving you the best results possible.
In an ideal situation, the PDF file is created from a professional desktop publishing application such as Adobe InDesign or QuarkXPress. But with that said, you need to remember that a quality PDF begins with a quality native application file – meaning, making sure it contains bleeds if necessary, images are placed with adequate resolution, images are of the correct color space (always grayscale or CMYK for print), quality fonts and spot colors are named properly.
The most common problem associated with PDFs are images that are in the wrong color space and images that contain inadequate resolution. A native file containing images with proper resolution ensures that they will prints crisp and sharp, with no loss of detail. If using images from a digital camera, it’s important to take a long, hard look at these to make sure they are of quality to give you the most professional printed piece possible.
To determine proper resolution, use the “two-times” equation. This means that the resolution of the images (pixels per inch, or PPI) must be twice the line screen (lines per inch) in which the job will print. For us, our offset press prints at 300 dpi. If your images are placed in your file at 100%, your photos need to be 300 dpi at 100% placement size for offset printing.
Images must be converted from RGB color space to CMYK color space for print production. This conversion process is more than just a mode in Photoshop. Considerations must be made for paper type (coated or uncoated), dot gain, and total ink coverage, just to name a few. If you need help in deciding if your photos are of the best quality, give your service provider a call and they can help determine these factors. The best policy is to request a color settings file from your print service provider, then load that color settings file into Photoshop.
The ability to embed fonts within a PDF is one of the format’s greatest strengths. When fonts are embedded in a PDF, a compressed, encoded set of characters will be included in the file. Be aware however, that some fonts contain licensing restrictions; this means they cannot be embedded into the PDF. Embedding fonts will give you the greatest outcome and help in font default problems on the printing end of your project.
Bleed and When You Need It
Missing bleeds in a PDF is also one of the top problems with PDF files. While missing bleeds can be fixed in the native application, repairing bleeds in a PDF can be a time-consuming process for your print service provider, and can sometimes result in production costs on your end. Make sure that adequate bleeds are created (we require an 1/8”) in the native application file and that they are included in the resultant PDF. (Ex: If you are printing an 8.5×11 document where your images go right to the edge, you want to make your document size 8.5×11 but then over lap those images an 1/8” over the bounding box.) In the export PDF dialog found in QuarkXPress and InDesign, there are options to include bleeds.
Spot or Process (CMYK)?
Defining color properly in the native application is a critical step in creating quality PDF files. If the document contains spot colors that will print on the press, make sure that they have not been converted to process in the native application. Again, correcting this within the PDFs is a very time-consuming procedure for the service provider and can result in extra art charges on your end.
Work With Your Printer
Finally, the last consideration for creating your PDFs is to work closely with your printer. One of the best things you can do is to ASK FOR HELP; ask for the Adobe PDF Settings they recommend for creating PDFs. The Adobe PDF Settings file is shared among all Adobe CS applications and can be found in the following locations:
Mac OS X : Library-Application Support-Adobe PDF-Settings
Remember, by taking the time to properly prepare your PDF file for print, you will save yourself time and money.
©This story courtesy of Blueline, the quarterly newsletter of the Printing Industries of Northern California (PINC) .