Work backwards from paper
Choose the physical width and the viewing distance first. A close-held print is commonly prepared around 300 pixels per inch; a wall print viewed from a metre can look entirely natural much lower. Multiplying the intended inches by that density gives the output pixel count the tool must meet.
The route starts at 2× because it is the least speculative enlargement and because width and height doubling means four times the memory, processing and encoded area already. Move to 4× only after the arithmetic says 2× is insufficient.
| Source | At 2× | Print at 300 ppi |
|---|---|---|
| 1200 × 800 | 2400 × 1600 | 8 × 5.3 inches |
| 1800 × 1200 | 3600 × 2400 | 12 × 8 inches |
| 2400 × 1600 | 4800 × 3200 | 16 × 10.7 inches |
Inspect the defects at their final scale
The loupe shows output pixels, which means sharpening halos, JPEG blocks and repeated edge patterns cannot hide behind a fitted preview. Compare hair, lettering and high-contrast diagonals. If the larger version merely makes a defect easier to see, adding more pixels is not improving the print.
Keep clean-up at zero on a clean source. On a rough small JPEG, raise it only until blocks stop being the first thing the eye sees; texture removed before enlargement does not return afterwards.
Related enlargement decisions
- Double the sizeThe factor with the least to apologise for. Opens at 2× on a sharp source.
- A rough small photoOpens with the clean-up pass on, because a 600-pixel JPEG carries more than a picture.
- What enlarging can and cannot get backWorked through at 2×, 4× and 8×, with the part that is a guess named as one.
- Where a trained model beats arithmetic, and where it doesn'tThe case for the classical path, made fairly, including the cases it loses.
