How to Sharpen a PDF

While you can’t truly sharpen a PDF in the same way you would a pixel based image there are some ways to increase the perceived sharpness of the PDF at least.

Method 1: PDF Editors with Image Enhancement Tools

Adobe Acrobat Pro:

  • Open the PDF.
  • Go to Tools –> Edit PDF.
  • Right click an image and select “Edit Image”.
  • In the “Object Data” tool window, find the “Sharpen” tool.
  • Experiment with different sharpening levels.
  • Save your changes.


  • Open the PDF and go to the “Edit PDF” section.
  • Double click on the image you want to sharpen.
  • In the pop up menu, select “Properties”.
  • Look for “Sharpen” or “Image Enhancement” tools (the naming varies between PDF editors) and adjust accordingly.
  • Save the PDF.

Method 2: Online PDF Editors

These are convenient if you don’t have dedicated PDF software:

Sejda ( Upload the PDF, select “Adjust”. Use tools like “Sharpen” or fine tune brightness and contrast.

Smallpdf ( Similar to Sejda, providing tools to improve clarity and readability.

Canva ( Great overall tool with a great looking interface that can help you sharpen the PDF with different proprietary tools.

Method 3: Preview (macOS)

Preview has basic sharpening and contrast adjustments:

  • Open the PDF in Preview.
  • Click the “Markup” icon (looks like a pen).
  • Select the “Adjust Color” tool (brightness/contrast slider icons).
  • Move the “Sharpness” slider to the right to increase sharpness.
  • Adjust contrast and brightness for better clarity.
  • Save the PDF.

Method 4: Rescanning/Reprinting for Scanned PDFs

If the original source document is available:

  • Rescan the document with a higher resolution setting.
  • Adjust the scanner’s contrast settings.
  • Convert the new, higher quality image to PDF.


Zoom In: Sometimes zooming into the PDF slightly will give the illusion of sharpness.

Font Smoothing: Some PDF viewers have a “Smooth Text” option that can improve readability.

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