600 DPI vs 1200 DPI
Use 1200 only for pure black-and-white line art and for scanning very small originals. For everything else, including photos and ordinary documents, 600 already exceeds what print or the eye can show.
| 600 DPI | 1200 DPI | |
|---|---|---|
| Pixels in an inch | 600 | 1200 |
| Pixels in a centimetre | 236.2 | 472.4 |
| Pixels in a square inch | 360,000 | 1,440,000 |
| 4 × 6 in photo | 2400 × 3600 | 4800 × 7200 |
| A4 page | 4961 × 7016 | 9921 × 14031 |
| US Letter page | 5100 × 6600 | 10200 × 13200 |
| A4 in megapixels | 35 | 139 |
| A4 uncompressed | 100 MB | 398 MB |
| Pixels blend from | 5.7 inches (15 cm) | 2.9 inches (7 cm) |
1200 DPI has 4 times the pixels of 600 DPI at the same print size. “Pixels blend from” is the distance at which 20/20 vision stops separating them.
When 600 DPI is the right choice
- Documents, text and line drawings for office printing.
- Scanning photo prints: a print rarely holds more detail than a 600 DPI scan captures.
When 1200 DPI is the right choice
- 1-bit line art for professional print, which is commonly supplied at 1200 DPI.
- Scanning small originals for enlargement, such as stamps, coins or fine engravings.
Why
Doubling from 600 to 1200 DPI again multiplies the pixel count by four. An A4 page is 4961 × 7016 pixels at 600 DPI and 9921 × 14031 at 1200 DPI, about 35 and 139 megapixels. Film is the exception that needs more still: a 35 mm frame is only 36 × 24 mm, so it is usually scanned at 2400 DPI or higher to get enough pixels for a print.