Optimal settings to create print-ready PDFs
Handing off finalized content to the press in the form of a high-resolution PDF is a common step in print workflows. Such a press-ready PDF file typically includes information relevant to high-quality printing—spot color data, fonts, trapping parameters, and overprint settings.
Adobe Acrobat or Adobe Distiller users often wonder what settings they should choose while generating press-ready PDFs. The purpose of this blog post is to ease that dilemma.
A use case
Let’s say you want to print a document as a poster. You select the High-Quality Print JobOptions settings in the PDF conversion settings. Later, when you send the documents to the printing agency or the latest printer you bought, you figure the printouts are not as bright as you’d have liked them to be. The pictures looked amazing on your computer monitor, but the printouts failed to reproduce that brilliance.
You tweak a few settings and customize them to match the desired output. However, after a few prints, you realize that the permutations and combinations you applied, although apparently working, do not match the desired quality.
If you know your print environment well and are conversant with Distiller, you can start pretty much anywhere and start adding and subtracting job parameters. For beginners, though, the various settings offered can be overwhelming.
Acrobat ships with several preinstalled JobOptions that you can use. In Acrobat Distiller, these settings are called Adobe PDF Settings (or JobOptions). Depending on your software program, these settings may also be called Adobe PDF Preset (in InDesign or Illustrator) or Conversion Settings (in the Adobe PDF menu item added by Acrobat PDFMaker to many apps).
These settings are suitable for different use cases and have a direct impact on the size of the PDF file created.
Using this table, you can make educated decisions about which JobOptions setting to pick for your files. For example, you could pick Standard if you intend to post the finished files on a website. When the files are heading out for high-resolution printing, you could use one of the commercial printing options.
Let’s explore some common PDF JobOptions settings and understand how they affect the conversion process:
High-Quality Print leaves the color unchanged. High-Quality Print was created for high-quality desktop printers rather than actual offset print production environments. The High-Quality Print settings might do OK in all print scenarios, but they may result in a not-so-well-compressed PDF file. Also, they may not preserve ICC color profiles.
Press Quality Print converts the document to the CMYK color model for print production. It also sets color working spaces. However, I wouldn’t recommend Press Quality settings for many contemporary print workflows, since they convert all colors to CMYK. In doing so, they eliminate true device independence and prevent you from taking advantage of any additional colorants and/or expanded gamut that the actual printer may provide.
PDF/X-1a: I recommend that you avoid these settings. They flatten your file and prevent you from editing any transparency that was present earlier.
Recommended options in different apps
Let’s return to our use case. For a PDF to be good enough for printing as a poster, it must preserve high resolution as well as high color quality. Often, posters are printed on devices that support more than just CMYK colorants. Colors such as O (orange), G (green), m (light magenta), and/or c (light cyan) may also be used, especially on wide-format inkjet devices. It is desirable that such PDFs retain any transparency and all colors, rendering inadequate the JobOptions settings we discussed so far.
If your source file is an InDesign document, I’d strongly recommend that you use the PDF/X-4 JobOptions setting with the following tweaks:
- Output: The Output intent profiles in the Output tab controls how colors and PDF/X output intent profiles are saved in the PDF file. Set the output intent to whatever print condition is expected. Otherwise, leave it at the default value.
- If you expect the poster to be viewed at a great distance, you might lower image downsampling values of 300/450, 300/450, and 1200/1800 to a suitable number.
Color, grayscale, and monochrome images should be downsampled to combine pixels in a sample area to make one larger pixel. You need to provide the resolution of your output device in DPI (Dots Per Inch) and specify a resolution in PPI (Pixels Per Inch).
- Typically, to get a PDF document with higher quality, the printer driver downsamples color images above 300 PPI to 450 DPI, grayscale images above 300 PPI to 450 DPI, and monochrome images above 1200 PPI to 1800 DPI.
- Export the PDF; don’t use Distiller to convert the PostScript (.ps) file. Also, don’t change the JobOptions to convert any colors since that would defeat the purpose of using PDF/X-4.
If your source file is an Illustrator document, ensure that images in it are linked and not embedded. Illustrator converts embedded images to CMYK—something we do not want.
Now, save the Illustrator file using the PDF/X-4 JobOptions settings with the same tweaks I advised for InDesign. However, save the file from within Illustrator instead of exporting it from InDesign.
Use the tweaked PDF/X-4 JobOptions for Photoshop files as well. Save the file as PDF from within Photoshop instead of exporting it.
Microsoft applications (Word/ PowerPoint)
Assuming that you have Acrobat DC installed, do the following:
- Open the file.
- Go to the Acrobat tab and, under Preferences, set the conversion settings to High-Quality Print.
- Click the Create PDF button from the Acrobat tab.
At times, you might observe that R-G-B text and vector artwork are DeviceGray whereas other colors are DeviceRGB. This should work OK for most printing scenarios unless the file contains transparency groups with RGB transparency blend color space specifications. Such transparency groups can cause havoc during printing. To fix this issue, you need to run a Preflight fixup to remove these transparency blend color space specifications. After this fix-up, any reasonable print service provider or print shop should be able to print the file without problems.
The Acrobat tab in PowerPoint for MacOS does not have any preference settings yet. All you can do is click the Create PDF button and specify where you want to place the file. If you print directly from Acrobat, the Advanced > Color Management print options provide an option to “treat grays as K-only grays”, fixing this problem during PostScript generation for printing. Otherwise, many (but not all) PDF Raster Image Processors (RIPs) provide a Digital FrontEnd-resident function for automatically fixing this issue. Each device is shipped with a DFE (Digital Front End) from the device manufacturer. The core piece of any digital production workflow is the DFE or the RIP, which actually performs the translation from PostScript or PDF code into the bitmaps that print. The kernels in the DFEs get updated on a regular basis to keep up with standards developments and other changes in market requirements, such as broader support of file types, color management, trapping, imposition, and more.
Using the above-mentioned settings, you’ll be surprised at how much you can do to improve your printouts with very little effort. The more you experiment with them, the better your prints become. What’s more: you’ll have learned a range of methods you can apply to any given situation. Once you have made the required changes to the file, perform a final check by running preflight in Acrobat. The preflight will highlight unembedded fonts, transparent objects, low-resolution images in the PDF file, and other similar issues. You might want to fix these issues prior to submitting your work. Once fixed, your PDF is press-ready.