Check the DPI of images in a PDF
Find photos that will print blurry. The check measures each image's real resolution at the size it's placed on the page.
Checked entirely in your browser. Your PDF is never uploaded.
How printed DPI is calculated
Effective DPI is the image's width in pixels divided by its printed width in inches. The same photo can be sharp or blurry depending on how big you print it:
| Photo width | Printed width | Effective DPI |
|---|---|---|
| 1200 px | 4 in | 300: sharp |
| 1200 px | 6 in | 200: may look soft up close |
| 1200 px | 10 in | 120: likely blurry |
Cropping inside a design app doesn't change this: the image keeps its pixels, but only part of it is visible.
Thresholds used
- 225 DPI or more: passes.
- 150–224 DPI: warning. Fine for most viewing distances, but fine detail may look soft.
- Under 150 DPI: likely to look blurry or pixelated.
- For large posters (a side longer than 17.5 in), the limits drop to 150 and 100 DPI because posters are viewed from further away.
Fixing low-resolution images
- Replace the image with the original, full-size file (photos from messaging apps and websites are often downsized).
- Print the image smaller, or crop less tightly.
- For logos and icons, use a vector version (SVG, EPS or PDF) so resolution doesn't apply.
Questions
My image file says 72 DPI. Is that a problem?
Not by itself. The DPI number stored in an image file is just a label. What matters is how many pixels end up in each printed inch, which depends on the size the image is placed at. That's what this check measures.
Can I just upscale the image to 300 DPI?
Upscaling adds pixels but not detail, so the print usually looks just as soft. A larger original photo, or printing the image smaller, is the real fix.
Why are some images skipped?
Tiny bitmaps used for gradients, fills and masks print smoothly whatever their resolution, and small icons under a quarter inch aren't worth flagging, so they're left out of the count.