It’s generally a good thing to be able to distinguish different file formats for different purposes – some formats work well for printing, while others exclusively work for the web.
The Portable Document Format, aka PDF, is one of those factotum formats. There’s a higher risk that you may commit mistakes when creating a press-ready PDF, especially if you unsure how to save them and what to do with them.
Here is a guide to the most used PDF versions and standards, what they mean, and when to use them.
PDFs and Print
When we talk about commercial printing, this is what all PDFs have to have in common:
- In 90% of cases, all colours have to be CMYK.
- All fonts need to be embedded because a person using your computer without your fonts won’t see the correct ones. Therefore, your designs won’t be printed properly. If you can’t embed the fonts for whatever reason, turn them into outlines.
- 99% of the times you have to account for bleed and cropping marks.
These are the qualities that all press-ready PDF files possess. However, there are some other variables that may or may not create problems such as colour space and transparency. It’s difficult for a designer to know what kind of RIP a printer uses. For a pre-press department, transparency is the biggest problem next to forgotten fonts and RGB images.
The problem with transparencies is that even though your file has passed your pre-flight checklist (yes it’s called like that for printing too!) with flying colours – no pun intended – transparency is one of those things that can give you unexpected results if your printer’s RIP doesn’t support it.
The different types of PDFs force the designer to do certain things to try and drop errors as much as possible. This is why they are called PDF standards. If the requirements of such standards are not followed, the validation fails and the designer has to go back and correct the problems before they reach the printer.
If you know about these standards and follow them, you will save yourself and the printer a big headache!
PDF Versions VS PDF Standards
Whenever Adobe releases a new Acrobat, like Acrobat 4, Acrobat 5, etc., they also release a new PDF version, i.e., the Acrobat program was able to include more things into PDF files, so the format itself evolved. When you read things such as PDF 1.3 or PDF 1.4 you are seeing the version of the PDF.
A PDF standard is a PDF that has a certain set or rules. For example, some standards want you to specify the colour profile you are going to use, e.g, Fogra27, Fogra 29, etc. Also, the specific profile of your PDF must be provided by your printer. Other standards want you to have bleed, crop marks, and so on.
Standards will include certain PDF versions in their specifications.
It’s the Acrobat 4 version. It supports CMYK, spot colours, and notes, although you can’t print these. Some security features are also supported. Because it does not support transparency, this is the PDF version that will create the least problems with printers.
Since we start talking about transparency support, some commercial printers RIPs might have issues dealing with this PDF version. However, this is becoming less and less of an issue.
The Acrobat 6’s version has improved compression techniques and introduced support for media files and layers. These are great features for screen viewing, but they do nothing for printing as you obviously can’t print videos.
There are later versions obviously as Acrobat has passed version 6 since a while, but for printing purposes you really don’t care about those.
The PDF/X Standard
There are a lot of PDF standards that “channel” the PDF format towards different directions: interaction, online viewing, printing, and so on. The one that is currently most used for printing is the PDF/X standard. If you want to make sure that your files will print correctly, try to follow this standard.
Let’s explore the two versions of this standard below.
Making a PDF/X-1a isn’t actually that difficult as many desktop publishing applications have a preset for that standard. However, if that choice isn’t available, you need to know what to do in order to abide by that standard, so here is a list of things for you to remember.
- The PDF version has to be 1.3.
- The PDF has to be a composite and not colour separated.
- All fonts have to be embedded or converted to outlines, while images have to be at least 300 PPI and also embedded.
- Lossless compression is allowed bar LZW, so beware of your embedded TIFFs as you can’t use the LZW compression on them for your PDF/X1-a files. JPEG is the only lossy compression allowed.
Further you have to specify:
- The Trim Box
- The Media Box
- The output intent, aka the ICC profile
- The PDF can only be CMYK or contain spot colours. No RGB or LAB colour modes allowed.
- Bleed Box and Crop Box are optional.
What is not allowed:
PDF/X-3 is a more advanced printing standard which allows you to do more things. As such, you can have problems, so ask your printer what they prefer. Aside from the things explained above for the PDF/X1-a, here is what you can do with PDF/X-3:
- You can use RGB graphics as long as you specify a colour profile.
- LAB mode is allowed.
- You don’t have to specify a colour profile for CMYK content, which makes it easier if you don’t have a specific profile from your printer
The PDF/X-3 standard is great for the prints you do in-house as well, i.e., when you use your laser printer, an inkjet and so on. Most office printers “assume” that you will be sending them RGB images and some of them have more inks than a commercial offset lithograph, so sending them RGB files might be better.
If you read all of this, you will know more than about 70% to 80% of graphic designers out there, so pat yourself on the back and go show the printers you know what you are doing!