Live Overlay Comparison Mode

PDF Studio Viewer comes with a Live PDF Overlay Comparison feature that allows you to overlay a second document onto the first in real time for a quick difference comparison.

How to compare two documents using Live Overlay Comparison

  1. Open the initial or first document in PDF Studio Viewer. This will become Document A in the comparison
  2. Go to View Tab > Compare Side by Side... in the toolbar.
  3. Select the second document that you wish to compare with Document A. This will become Document B in the comparison
  4. You will now see Document A (on the left) and Document B (on the right) opened side by side in the same PDF Studio Viewer window.
  5. Click on the   Live Overlay Mode button on the top right of the viewing area
  6. You will now see Document B overlayed onto Document A and the Compare Overlay dialog that can be used to make any alignment changes to Document B (in real time) if needed to correctly match up the documents.

Note: The overlay view can also be printed by printing the document while the overlay view is enabled.

Image Overlay Options:


Choose to display both or each document individually

Click on the icon to minimize the overlay comparison settings dialog. It will be docked at the bottom right corner of the PDF Studio window. Click on the docked button to restore the dialog.


Color - select the color of each document (the default colors generally provide the best results). See Choosing colors for overlay PDF comparison.

X & Y - adjust the X & Y values of Document B to move it left, right, up, or down

Rotate-  adjust the rotation of Document B if needed

Scale - make Document B smaller or larger if needed.

Note: The scale option has a minimum of 1 and a maximum value of 999.

Additional Options

Annotations & Markups - At any time during the comparison you can only annotate or markup any changes in Document A.*

Note: It is worth noting that all annotation and text markup tools, as well as other PDF editing tools, are still active while in comparison overlay view, allowing to mark up and modify the original PDF.  One can also easily switch back and forth between the overlay comparison view and the side by side comparison view (where the 2 documents are displayed side by side in a synchronized way). In side by side comparison, it is possible to annotate the second document to add sticky notes and text highlights (look under the right-click context menu).

Switching Comparison Modes - You can also switch over to our  Side by Side Comparison mode by clicking on the Side by Side button in the Overlay Comparison dialog. When switching back and forth the scale values will be remembered until a new document is opened for comparison.

Exporting - Once you've completed your comparison you can export the comparison into a single document with the Overlay Comparison View as the as the base layer and Documents A & B as layers within the document. If you have completed your comparison and want to exit the comparison mode just close the comparison tool to return back to Document A.

Note: The overlay view can also be printed by printing the document while the overlay view is enabled.


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