A PDF file is a ‘Portable Document Format’ used for sending files that people can read without having to have expensive Design packages. It also enables you to make files read-only where changes cannot be made if you don’t want them to. If a file is to be printed it must be in a CMYK format.
A PDF file is easily checked as to what format it is saved in, RGB or CMYK. All you need is Adobe Acrobat. If you are sending the file to print it must be in CMYK format.
For those that just use PDFs to send docs to co-workers or club members, it doesn’t really matter what the format is. It only becomes relevant if it is going to be printed.
CMYK generates better color matching in images within the file. Let’s look at how we check and how we convert it to CMYK.
How can I check if the file is CMYK?
To check the file first you need to open the file using Adobe Acrobat. If you don’t already have it it is free to download and also part of the Creative Cloud suite.
At the top of the screen select Tools
Scroll down the tools page until you reach Protect and Standardize.
Click on Print Production
This will give you a sidebar. Click on Output Preview
In the Show Section, click on the down tab to select CMYK
Everything that is CMYK in your file should still be in place. If however certain images are missing then these are most likely to have been saved as RGB. You can test this with the same method except this time select RBG in the drop-down instead of CMYK. Any images that now appear are RGB files.
Note that because my file is all CMYK, no items are showing when RGB is selected
Why does it need to be CMYK?
Now that we have established what the file is saved as or at least part or all of it. It is important to know that if your file is going to be sent to print it must be saved as CMYK format.
What you ask will happen if I don’t make the changes? Well, the images will still print but they will have a different color tone to your CMYK images and your document will look a little odd.
Let’s look at how we can easily change the file format to all CMYK.
Open the file in Adobe Acrobat.
Click on Tools as before and click on print production as before but this time on the side bar click on ‘Convert Colors’
Select ‘Any Object, Any Colorspace, Any Profile at the top of the box (It sometimes is the only one available)
In Conversion Attributes, click on Conversion Profile. Scroll down to Photoshop 5 and Click Embed.
At the bottom of the box ‘Convert Options’ tick all three boxes.
Click OK and File Save at the top.
Now your file is Print Ready in CMYK.
Traditional printers use four-color separation plates. C (Cyan) M (Magenta) Y (Yellow) and K (Black). These colors were printed onto separate metal plates and each color is overprinted on a four-color press to make the finished document.
Generally, all printing is now done digitally it still requires four colors. Even in your most basic home printer, you have either a K – black cartridge and a CMY cartridge or four individual cartridges. All are based on the original concept. This means that even if you are printing a poster/ flyer or a presentation it is important your PDF is CMYK format.
Ensure no one alters your file
The last point I would like to make is that you ensure your file is not altered in any way by anyone else. along the way.
As a graphic designer, over the years I have nearly been caught out by this and in the early days fully caught! Someone can go in and alter your file if you don’t protect it properly. To make sure this doesn’t happen we go back into Adobe Acrobat.
In the same area
Tools – Protect and Standardize. Click on Protect this time.
Then Advanced Options
A security box will pop up, click on Yes to proceed.
In the new box that appears there is a ‘Permissions’ area. Check this box.
Printing allowed – In the drop-down select High Resolution
Changes Allowed – None
In the Options Section
The higher the Acrobat Version the better, as time has moved on Acrobat versions have become more security aware, so the higher the version, the higher the latest tech it has.
Make sure at the bottom that the Radio button is checked on Encrypt all contents
Click Ok and then go to File Save.
Your file is now fully print ready and secure to send to a third party.
I’ve written a lot on common InDesign issues, which might help you on your InDesign journey:
If you are curious about other Design issues, check out the FAQ category