InDesign Tip: Making PDFs for print
In the process of compiling the sixth Evil Inc book, I ran across the solution to a problem that’s been plaguing me ever since I started printing in color.
I lay out my books using Adobe InDesign and export a PDF to send to the printer. In this case, the printer, Transcontinental, gives me a “PDF preset” to use so the PDF is created to their standards.
Once I uploaded the PDF, I was alerted that some of the images were presenting at a low resolution.
I know this isn’t the case because… well, heck, because I’ve been doing this kind of work for twenty years now. 🙂
So I started hunting around, and I finally found the culprit. Part of Transcon’s PDF preset — in fact, part of practically every PDF preset — has image compression built in. After all, that’s what a PDF file does… it compresses the document for easy use.
But I’m not looking for easy. I’m looking for quality.
So I modified the PDF preset and — viola — my resolution problems disappeared.
Modify a PDF preset to optimize your image quality
Here’s a look at the dialogue box you get when you export a PDF from InDesign. Click on “Compression” in the left-hand column to get the view you see below.
You see all those instances in which it says “Compression: Automatic (JPEG)“? Click on the toggle bar in each of these fields (Color Images, Greyscale Images, Monochrome Images) and change it to NONE.
Now export the PDF.
Warning: Without the compression, your file size will be huge. My 104-page book clocked in at 2.5G.
And it took a little while to upload, but I think the results in image quality were worth it.
Why remove the compression?
Even if you toggle the Image Quality beneath each of those to “Maximum,” it’s still a JPEG. I’m a little bit of a hardnose on this issue, but I feel strongly that JPEGs are for image storage — not printing. And I refuse to beleive that even a JPEG saved to its maximum quality is as good as the TIFFs that I prepped for the book.
Mind you, my case is a little different than yours might be. My books don’t use each of the panels of each of the strips at 100%. Some of them are reduced — and some of them are enlarged — by a fairly significant amount. My guess is that when I enlarged some of the files in InDesign and then coverted those images to JPEGs through the PDF-exporting procedure, their resolution suffered as a result.
In general, I would caution you strongly against trying to enlarge images. It’s always safe to reduce them, but enlarging them puts you in some pretty choppy water to navigate. When I do it, I understand the risks I’m taking, and I’m prepared to see a little image degradation in those instances. Unless you can say the same, I’d avoid enlarging images when preparing your books.