How to Check DPI of PDF

Posted by on Jan 18, 2012 in Tutorials | 6 Comments
How to Check DPI of PDF

I recently found my self scouring the web to find out how to check the dpi (dots per inch) of a PDF I had created.  I figured it would be quite simple, but there was not much help out there, so I leaned on my AIGA listserv to see if they could help. They came through with flying colors. Here is a guide to checking the dpi of a pdf.

First off I am using Adobe Acrobat Professional 8.1.6 running on Mac OS X 10.4.11 and have created the pdf with InDesign C3. This wont work if you are just using Adobe Reader.

Step 1

Open the .pdf file you are looking to check out in Adobe Acrobat Professional.

Once the file is open, click “preflight…” under the “Advanced” menu drop down [Advanced–>preflight...]

Preflight

This should open up a dialogue box like the one below.

Preflight Dialogue Box

Step 2

Click the triangle next to the PDF analysis category to reveal all its options.

PDF Analysis

Scroll down and click on the “List images below 250 ppi”. As a side note, ppi (points per inch) is the same as dpi.
*Some versions might not have all the tasks categorized, so just scroll and find “List images below 250 ppi”.

List imaged below 250 dpi

Step 3

As you will notice, for my purposes 250 ppi will not work (I need 800), so we will have to edit it. So click on the Edit button in the window’s menu bar while you have “List images below 250 ppi” selected. If 250 ppi works for you, skip to Step 6.
*Please note that Adobe Acrobat Professional version 8.1.6 does not give me the option to duplicate the task and then edit. I just edited this one because it will serve the same purpose of finding images below 250 when I execute it.

Click Edit

Step 4

Under the Edit Profile, you will need to change the Name and the Purpose to correspond with your needs. Since I wanted to make sure my pdf was 800 dpi, I need to edit the task so that it checks for images under 801 dpi. If I make it 800 dpi and it happens to be 800 dpi, then this task will run clean thereby not telling me the dpi of my pdf.

Edit Dialog Boxes

Edited

Setp 5

Next, click on the “Images” category under the “List images below 801 ppi” (the name has been automatically updated once I edited it in the previous step) and change 250 to 801 in the dialogue box “lower than” under the “Resolution of color and grayscale images is”. Click OK.

Below 801 ppi

Change to lower than 801

Step 6

Now you need to execute the task by clicking “Execute” while the “List images below 801 ppi” is selected. You should have automatically been taken back to the “Profiles” tab once you clicked OK in the last step.

Profiles

When the task is executing you should get a box that looks like this:

What it looks like while executing

Step 7

Once the file has finished executing, the “Results” tab should appear and if your pdf was below 801 dpi (or your desired dpi) a registry will appear that looks like this:

Almost There

Click the expanding arrow next to the first “Information Dot” to reveal your desired information. According to this summary, my file was not the desired 800 dpi, rather it was 300 dpi. Now I know I need to go back into InDesign and re-export my file with different settings to make my file 800 dpi. Then I can recheck it using steps 1, 2, 6 and 7. You wont need to edit the task again because it will already be saved.

Finished!

I hope this guide will be usefull to some of you. It’s a pretty basic operation, you just might not know where the appropriate tools are to perform it. Heck, I didn’t.

6 Comments

  1. Ag
    August 31, 2012

    Hi,
    Very usefull, thank you :)

    Reply
  2. Benton
    November 28, 2012

    A lovely explanation

    Reply
  3. Elizabeth
    January 9, 2013

    Thank you so much! I was searching all over for this, too. Very helpful.

    Reply
  4. pranab
    June 11, 2013

    Nice article; thanks.

    Reply
  5. joe
    August 4, 2013

    Great article but clearly for an older version. I have XI and I can’t find anything about listing images less than a specified ppi. Any suggestions would be greatly appreciated. Thanks.

    Reply
    • Admin
      August 6, 2013

      Hi Joe, Thanks for letting me know. I figured this would happen at some point.

      I was able to achieve the same results in the Adobe Acrobat Pro 10.1.7 with the following steps.

      Open pdf.

      Go to Edit > Preflight

      Under the Profiles tab, click on Options (Upper Right) > Create New Preflight Profile…

      This will bring up a new dialog box. Title and describe this new profile as you will.

      In the left sidebar click on Images and utilize the Lower / Higher threshold values to set your trigger points. For my example above I would use “Lower Than” and “800″.

      Create the profile, select said profile in the original Preflight dialog box and then click analyze. If your your newly created Profile turns up in your Results tab you are good to go!

      Reply

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