Thoughts on Preparing Files for Press

It may sound like I plan to tell you exactly how to prepare final files for your printer, but that's not completely true. In my experience it has been more prudent to ask each print provider for this information on a case by case basis.

Why? Because different printers have different workflows, and over time they change these practices, and they also upgrade their equipment. In addition, general practices in the printing industry change over time.

(I used to send hard-copy paste-ups, called mechanicals, to the printer for each job. Back then, not only did we not transmit electronic files to press, but back in the 1990s we were just starting to scan our own images, and we sent jobs to press on high-capacity drives—not even CDs and certainly not over the internet.)

In this light, I'd like to suggest some general rules of thumb, things to consider when determining with your particular printer exactly what he needs you to provide for a particular job.

1. When you are ready to go to press, ask your printer how you should prepare the final print-ready PDFs. He will probably have a list on his website or perhaps even a few blog articles directly pertinent to his prepress workflow and equipment.

2. In some cases a commercial printing vendor (for instance, a printer that prints high-end perfect-bound books with French flaps for one of my clients) will want not only PDF files with all fonts embedded but also the native file. The native file is the InDesign or Photoshop document from which you will have distilled the PDF for your job. Why does your printer want this? Because in some cases you will have missed something in your PDF file set up, and if your printer has the original file, he can often fix the document without needing to have you make the changes and resubmit the job. Granted, not all printers will do this. Some will just tell you what's wrong, and it will be up to you to make the corrections and upload the file again.

3. After you have a print-ready PDF file (and a native file, if appropriate), ask your printer about file-transfer protocols. In some cases printers have dedicated links on their websites for you to use to transfer files. Particularly in the case of native art files created in InDesign and Photoshop, you will be working with especially large documents. So ask your print provider what their size limit is for transferring art files.

4. Some of the printers I work with use third-party applications for file uploads. For instance, WeTransfer allows you to send and receive 200 GB files (or smaller) depending on your particular subscription. Check into free subscriptions as well (WeTransfer allows 2GB file uploads in the free version). To use these services, you upload your files to a cloud server and provide the email address of the recipient. The WeTransfer application alerts your recipient, who can then download the file from the cloud server. There are actually a number of similar services as well, such as DropBox.

5. When you're preparing art for a print book (as one of my clients has been doing recently), the covers can be a challenge to transfer to the printer. In my client's case, although the entire text block is an especially small PDF file (the perfect-bound book has all-black text, is 240 pages, and has a 5.5" x 8.5" format), nevertheless, the covers of these perfect-bound books are complex and therefore huge. This is when you need a service like WeTransfer or DropBox.

6. Based on my experience, I think it's wise to compress your files into what is called an archive before you submit them. Archives are smaller than native files and hence can be transferred more quickly, but that's not why I prefer them. They protect native InDesign and Photoshop files and PDF files from corruption in their travels across the internet.

7. For a perfect-bound book or case-bound book, I always request cover templates from the printer based on the page count and the caliper of the paper. For instance, a particular 60# smooth white text might have a caliper of 466 ppi (pages per inch). This means that if your book is 466 pages, the spine will be one inch thick. For a 233-page book, the spine will be half an inch thick. (Granted, printers' press signatures would actually have page counts that are multiples of 32, 16, 8, and then 4 pages rather than these arbitrary numbers—466 or 233—but to give you the general idea, I've made some allowances.)

8. If you are designing a book cover, you are responsible for handing off to the printer an accurate file with (reading from left to right on the print side) a 3.5" French flap (if any), a 5.5" x 8.5" back cover, the spine, a 5.5" x 8.5" front cover, and a 3.5" French flap (if any)--all seamlessly attached. The file also has to include bleeds and usually crop marks. It's crucial for your measurements to be precise and accurate. If your printer provides not only a spine width but an actual drawing of all panels of the cover, it's much easier for you. So definitely ask for one. Otherwise, if your math is wrong, your cover art can wind up where you don't expect it to be once the book has been printed and bound. (For instance, the text on your book spine might not be precisely centered between the front and back cover. Ouch.)

9. Remember to add bleeds if any image extends off the page, and make sure this is reflected in the PDF file as well as the native InDesign file. (It's easy to forget this part, so print out a PDF of the cover to check everything.)

10. Many printers will want book pages (for instance, for a perfect-bound book) provided in the PDF file as individual pages rather than as two-page spreads. Presumably this is so the pages can be moved around as necessary as the prepress professional imposes the book (organizes the individual pages on the printing plate such that when the press form has been printed, folded, and trimmed, the 16 or 32 pages of the press form will fall in the correct order).

11. Some printers' prepress departments will want you to include crop marks on the pages in your PDF file. Others I have worked with will want you to omit crop marks. Often these decisions are included in a computer file (a collection of preset preferences you can use when distilling a native InDesign or Photoshop file into a print-ready PDF).

12. On an entirely different note, the client I've been using for these examples creates his book covers in Photoshop rather than InDesign. That is, he does both the imagery and all of the text on the front cover and flaps right in Photoshop. Since the covers include a lot of text that must be readable, it's important for this text to be of sufficient resolution, or the edges of the bitmapped type will be fuzzy.

13. Using text layers in Photoshop, it is therefore possible for my client to first add text to an image as editable words. Then he can adjust the words as necessary (both the alphanumeric characters and their graphic characteristics such as size and font).

14. Because words on this Photoshop text layer are composed of Bezier curves (vectors or lines rather than bitmaps or dots), until he flattens the Photoshop file, which merges all the separate layers and at the same time turns vector type into bitmaps, his type will be of the highest resolution possible. It can be enlarged and reduced without any change in resolution until the final transition from vector (mathematical Bezier curves) to raster (or bitmapped) text.

15. Therefore, it is essential (in your own work) if you're creating type in Photoshop to find out from your printer what resolution the text must be. It is also possible that your printer will want a copy of the Photoshop art file in native form with all layers intact, so he can alter the Photoshop file if there are problems. Let your printer know if you are using Photoshop (for a poster or book cover, for instance) since he may assume you're using InDesign.

16. It never hurts to befriend someone in your printer's prepress division. Granted, any problems will be flagged in the report you receive after your files have been through a preflight check. However, it's always better to have the answers to your questions at the beginning of the process so you can produce the most accurate files possible the first time. Since many of the issues I've identified are treated differently from printer to printer, it is often helpful to email questions directly to a prepress professional. Customer service reps are often quite knowledgeable as well.

[Steven Waxman is a printing consultant. He teaches corporations how to save money buying printing, brokers printing services, and teaches prepress techniques. Steven has been in the printing industry for thirty-three years working as a writer, editor, print buyer, photographer, graphic designer, art director, and production manager.]