A PrintScale guide
Why does my print look blurry when the photo looks sharp on screen?
A screen often shows a reduced preview. A large print spreads the original pixels across a much bigger physical area.
By PrintScale · Updated
A small preview can conceal problems
When a 4,000-pixel-wide photo is displayed in a much smaller browser window, many source pixels are combined for display. Small defects can become less visible. A print at a larger physical size is a different viewing situation, so a crisp preview cannot prove that the source will hold up.
Changing only the DPI metadata does not add image detail. Effective print density comes from the number of pixels divided by the printed size in inches. Increasing the intended size without increasing the pixels reduces that density.
Diagnose the kind of softness
- If individual pixels or stair-stepped edges become visible, check the image dimensions and print density.
- If subjects are soft even at full pixel scale, check focus or camera motion in the original.
- If you see blocks or rings around edges, examine whether a messaging app or repeated JPEG saves compressed the file.
- If a proof differs from the image you supplied, check the printer's scaling, paper settings and sharpening workflow.
What happens as the same photo gets larger
This table uses one unchanged 4,000 × 3,000 pixel image, without cropping or resampling. Print sizes are rounded to two decimal places; image density is the exact setting used in the calculation.
| Source pixels | Image density | Print size, inches | Print size, cm |
|---|---|---|---|
| 4,000 × 3,000 | 600 PPI | 6.67 × 5.00 | 16.93 × 12.70 |
| 4,000 × 3,000 | 300 PPI | 13.33 × 10.00 | 33.87 × 25.40 |
| 4,000 × 3,000 | 240 PPI | 16.67 × 12.50 | 42.33 × 31.75 |
| 4,000 × 3,000 | 150 PPI | 26.67 × 20.00 | 67.73 × 50.80 |
| 4,000 × 3,000 | 100 PPI | 40.00 × 30.00 | 101.60 × 76.20 |
Improve the source, then choose the size
Start from the original camera file when possible. Make the final crop, avoid unnecessary intermediate JPEG saves and check whether a smaller print would meet your needs. Sharpening can improve edge contrast, but cannot reliably repair an out-of-focus subject.
AI upscaling can create a more usable enlargement, but it can also reconstruct details incorrectly. Inspect lettering, faces and repetitive patterns. Print a small crop at the intended scale before committing to an expensive large print.
Adobe explains why image pixel dimensions and resolution are different. Calculate your file's print sizes to check the numbers first.
When you are ready to compare an enlargement, open PrintScale.