Choose the size for the job
You can keep an approved 8 × 10 composition when moving to 16 × 20, but you cannot keep the same PPI from the same pixels. This makes the size a useful example of why crop shape and image resolution must be checked separately.
| Measurement | Value |
|---|---|
| Inches | 16 × 20 |
| Centimetres | 40.64 × 50.8 |
| Millimetres | 406.4 × 508 |
| Short-edge-to-long-edge ratio | 4:5 |
Pixel examples
These examples multiply each edge in inches by the stated PPI. They describe pixel counts for the chosen size, not a universal pass or fail rule for appearance. Use the retained pixels after cropping when checking an existing photo.
| Example PPI | Pixels |
|---|---|
| 150 | 2,400 × 3,000 |
| 240 | 3,840 × 4,800 |
| 300 | 4,800 × 6,000 |
A worked example
A 6000 × 4000 landscape source filling a 20 × 16 frame retains 5000 × 4000 pixels. Its effective PPI is 250 and the crop removes about 16.67% of the original area. At 10 × 8 inches, that same retained rectangle gives 500 PPI. Moving the focal position changes the selected scene, not either PPI value.
Before you print
On A2 paper, a portrait 16 × 20 image leaves only 6.8 mm at each side, despite 43 mm above and below. Do not assume that because the image fits the sheet, it fits the printer’s printable region. If edge space is insufficient, use a larger sheet or a smaller image.