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Why is my PDF to PNG export blurry? (and how to fix it)

By DeckleUpdated

A PNG exported from a PDF looks blurry when it has too few pixels for the size you view it at. Export again from PDF to PNG with Resolution set to Standard or Print, and the text and lines will be sharper. If the PDF page is itself a low-resolution scan, a higher setting makes the image bigger but cannot add detail that was never there.

PDF to PNG

Same physical page, more pixels

150 DPI

Letter: 1,275 × 1,650 pixels

300 DPI

Letter: 2,550 × 3,300 pixels

Double each dimension → four times the pixels

Example calculation · nominal sizes for an 8.5 × 11-inch page. Actual exports depend on page geometry and rounding.

How to fix a blurry PDF to PNG export

  1. Open the PNG and note its pixel size. Most image viewers show it in the file information.
  2. Open PDF to PNG and choose the same PDF, or drop it onto the page.
  3. Under Resolution, choose the next step up: Standard (150 DPI) instead of Screen, or Print (300 DPI) instead of Standard.
  4. If you only need one or two pages, choose Choose pages and type them, such as 5.
  5. Choose Export images and download the new PNG.
  6. Open it at the size it will be shown, not zoomed in, and check the smallest text.

The summary at the top of the settings shows the DPI before you export, so you can confirm the change took effect.

Why the image looks soft

A PDF stores most text and drawings as shapes, which stay sharp at any zoom. A PNG is a fixed grid of pixels. When you export at Screen, an A4 page becomes about 595 × 842 pixels, roughly one pixel per typographic point. That is fine for a thumbnail, but 10-point body text gets about ten pixels of height per line, and stretching the image on a large screen spreads those pixels out until edges blur.

Resolution A4 page in pixels 10-point text height
Screen (72 DPI) about 595 × 842 about 10 pixels
Standard (150 DPI) about 1240 × 1754 about 21 pixels
Print (300 DPI) about 2480 × 3508 about 42 pixels

Example: you export a four-page specification at Screen and paste page 3 into a wiki that shows images 1200 pixels wide. The wiki stretches a 595-pixel image to twice its size, and the text looks fuzzy. Exported at Standard, the same page is 1240 pixels wide and fills the column without stretching.

Check where the blur comes from

Not every soft image is a resolution problem. Work through these in order:

  • The viewer is scaling it. Many apps and websites resize images to fit. View the PNG at 100% to see its real sharpness.
  • The page is a scan. Zoom into the PDF itself. If the text is already fuzzy there, the page is a picture, and no export setting will sharpen it. Text PDF or image PDF shows how to tell.
  • Something compressed it later. Chat apps and some upload forms recompress images. Compare the file you downloaded with the one the recipient received.
  • It was saved as JPG. A JPG shows soft halos around text. Check the file extension and export from PDF to PNG if you want a lossless image.

When the higher setting is refused

Each image is limited to 16 megapixels on most computers and Android devices, and 4 megapixels on an iPhone, an iPad or a device with little memory. An A4 page at Print is about 8.7 megapixels, so on an iPhone or iPad the export stops before any image is written, with a message that the file is larger than the device can process. Use Standard there, or export at Print on a computer. Calculating pixels from DPI covers larger pages.

Tips

  • Match the resolution to the display width. For an image shown 1200 pixels wide, Standard on an A4 page is enough.
  • Use Print when you will crop. Cutting one chart out of a page leaves a fraction of the pixels.
  • Export only the page you are fixing. Choose pages saves time on long documents.
  • Keep the PDF for close reading. If people need to zoom deep into small print, send the PDF alongside the image.

Frequently asked questions

What resolution makes a sharp PNG from a PDF?

Standard (150 DPI) is sharp for most screens. Use Print (300 DPI) for printing, cropping or very small text.

Can I go above 300 DPI?

No. Print at 300 DPI is the highest setting, and it is enough for printing at the page's original size.

Why does my PNG look sharp on my computer but blurry on the website?

The site is probably resizing or recompressing it. Upload an image close to the width the site displays.

Will a higher resolution fix a blurry scanned PDF?

No. A scan holds only the detail captured by the scanner. Exporting it at a higher DPI enlarges the same detail.

Related tools

  • PDF to PNG to export again at a higher resolution
  • PDF to JPG for smaller files of photo-heavy pages
  • PDF to text when you need the words, not an image of them

Sources