Writing and editing are hard enough. Then you have to format your file to meet printer expectations so you can self-publish. It’s no easy task. One of the often unmentioned aspects is today’s topic: what it means to generate a ‘print-ready PDF.’
A Disclaimer: every print facility is going to have some specific requirements. We’re going to focus on Lulu’s Print-Ready file requirements here. They will NOT match every book printer around the world, so be sure to check with any printer you might use to get their specifications before submitting your file.
What is a Print-Ready File?
The name kind of says it all. A Print-Ready file is one prepared to the printer’s specification.
Print-Ready files should always be a PDF file.
When you format your book, you create a file. Most likely a DOCX or DOC from Word or an INDD from InDesign. This file may be a beautiful representation of your book. But it is not yet a Print-Ready file. In particular, your file format matters here. While software like InDesign and Word have print capabilities, the file they actually send to the printer (be it an at home printer or a large scale book manufacturer) is a PDF.
What is a PDF?
Introduced nearly 30 years about by Adobe, the Portable Document Format (or PDF) is a file format designed to ease the sharing and distribution of content. PDFs are the single most versatile and simple to share a file, offering consistency across a range of writing, editing, and design platforms.
Likewise, a variety of PDF viewers and PDF readers make it easy to share files.
No matter how what your preferred book layout software, you’ll need to adhere to the requirements for a PDF that Lulu’s printers can work with.
A Print-Ready File is always a PDF, and a Print-Ready PDF always uses the printer-on-demand provider’s specifications.
Lulu has a set of rules we need files to adhere to. Don’t get stressed though! These aren’t difficult to apply to most files and the software you use to create your PDF will almost always cover many of these elements for you. But not all of them. It’s valuable to understand the recommendations and requirements for your book design and file.
1. Image Resolution
Look for 300 dots per inch (dpi) for all your images. You’ll also need to look at your software for the best way to output a PDF that retains the image resolution. PDF and image compression is common for software like MS Word, so be on the lookout for anything that may shrink your file size.
Now, if the original image is less than 300 dpi, it may not be possible to achieve the image resolution we require. That’s okay. You can use lower resolution images, but the print quality may be off. Grainy or pixelated images are the most common issue you’ll see with lower resolution images.
I strongly recommend using high resolution images in your file.
2. Color Space
Color Space defines the specific set of colors and how they are organized. Importantly, you want to be sure your file uses the same color space our printers use so that we can be sure to the colors you see on your screen match the colors in the printed book.
For Lulu, we prefer sRGB and CMYK color. If you’re working in Word, you’ll need to be sure your images are already using sRGB or CMYK for your images. Word will only export at the given settings, so you won’t have a lot of options to control the image quality once you’re in Word.
That’s one of the primary reasons I tend to shy away from recommending Word for custom book designs that incorporate images. Software like InDesign, Affinity Publisher, or even Scribus offers more control over a range of settings, including image quality and color space.
3. Crop Marks
Traditionally, crop marks indicate where the printers should trim the page. Also called ‘trim lines’ the crops show up in the corners to allow the paper cutter to align and perform a straight cut.
It’s very important to note that Lulu does NOT use crop marks. Our printers use a trimming process based on the book size you’ve selected. If crop marks are present, there’s a good chance the marks will appear as dark lines in the corners of your pages.
Crop marks are helpful when laying out your file. Just be sure to turn them off before exporting your final PDF.
The Bleed is a slightly larger margin applied to the edge of every page to ensure the page can be trimmed down to the final size. For most common printers, bleed is 0.125” on all sides of the page.
Take note: all files created for printing have Bleed.
A 6×9” book would actually be printed at 6.25×9.25”. Once the pages are printed out, the 0.125” on each side are trimmed down prior to binding.
A book file NEEDS to include bleeds if you have content (like images or background color) that extends to the edge of the page. A file that does not include that extra 0.125” will still be printed with the bleed margin. The result can be pages with a thin white border.
I recommend you create your file with bleeds, no matter what kind of book you’re creating. In Word, this means adjusting your page size and margins to allow for that extra 0.125”. Other file layout programs, like InDesign, will allow you to set up your file for bleeds when you create the document.
The above image highlights the dangers of printing without bleed. The cut edge of the page is the black border, leaving the page on the right with white edges around the light-blue background. For those interested in further reading about graphic design and bleed, I recommend this article from Stack Exchange.
While there are many compelling reasons to use common fonts for your book, you might want to use a unique font for some chapter titles. Or for the title and half-title pages. Or even the entire book.
Just be aware that using uncommon or paid fonts can present a number of problems. The most pressing issue is that the printer may not own or have the rights to use that font. Fortunately, there is a simple way to ensure your fonts render perfectly for printing.
You need to embed all fonts in your file.
The procedure for embedding fonts is different for all programs, but once you have your PDF created, you can use Adobe Acrobat or Reader to view the PDF specifications and verify if the fonts are embedded.
Look under File > Properties > Fonts
The text (Embedded Subset) indicates the font has been embedded properly.
The most important role your print-on-demand company provides is the Print-Ready Check. You might even notice it happening; when you upload your PDF documents we do a thorough check to make certain our printers can print your document.
I hope this helps demystify Print-Ready files and how important it is for you to make sure your file is prepared for printing before you send it to Lulu or your print-on-demand service of choice.
Drop any specific questions in the comments and I’ll do my best to elaborate!
Paul is the Senior Copywriter at Lulu, responsible for all the words you see on our site (misspellings included). He also manages the community site – http://connect.lulu.com/en/ – and in his free time, he’s an avid reader and short story writer.