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I turned a PDF price table into an image but the small numbers blur when zoomed in; how do I fix it?

Convert again at 200 or 300 DPI and choose PNG. At 96 DPI a line of 8 point text gets only about 11 pixels from top to bottom, which is not enough to draw an 8 or a 3 cleanly. At 200 DPI it gets about 23 pixels, and the figures stay crisp even when zoomed.

Published · 3 min read

How many pixels does a small figure get?

Price tables are usually set in small type, 8 or 9 points, so the columns fit. When converting, that size is multiplied by the DPI divided by 72, like everything else on the page. Here is an 8 point line after conversion:

  • 72 DPI: about 8 pixels for the whole line. Figures turn into smudges.
  • 96 DPI: about 11 pixels. Readable at normal size on screen, but it blurs at the first zoom.
  • 200 DPI: about 23 pixels. Clear figures, and a 6 is easy to tell from an 8.
  • 300 DPI: about 34 pixels. Right when the customer will print the image or zoom a lot.

The problem is neither the tool nor the file. A phone can only enlarge the pixels that exist; it cannot invent ones that were never drawn. So the pixels have to be there from the start.

Settings that suit a price table

  1. Open PDF to images, choose the file and type only the page with the table.
  2. Choose PNG. It keeps the edges of the figures sharp and avoids the faint haze around characters that low quality JPEG adds.
  3. Start at 200 DPI. An A4 page becomes 1654 × 2339 px.
  4. Convert, then open the image on your phone and zoom into the smallest figure.
  5. If it is still not clear enough, convert again at 300 DPI, which makes the page 2481 × 3508 px.

If it has to be JPEG

Some platforms or systems only take JPEG. In that case push the JPEG quality slider to 90 or above. Low quality leaves grey ghosts around black figures on a white background, and tables are exactly where they show most. Compare the size shown under each image after converting, and pick the lowest quality where the ghosts do not appear.

When no DPI is enough

If the price table in the original file is itself a low quality scan, a higher DPI will not help, because the tool draws what the file contains. Try selecting a figure in your PDF reader: if you cannot, it is a picture, and the fix is to ask whoever designed the table for the original. And if the table is long and page wide, consider sending the PDF itself, which customers can zoom without any blur because its text is not pixels.

Common questions

Does a higher DPI change how the font looks?

No, the same font is simply drawn with more pixels. If the font was not embedded in the file, though, it may be replaced with a close match.

The 300 DPI image is too heavy for WhatsApp. What now?

Try 200 first. It is usually enough for 8 point figures and much lighter.

Should I convert the whole page or crop the table?

Convert the page at the right DPI, then crop the table if you like. Cropping does not reduce the sharpness of what remains.