REFERENCE
Five useful print ratio families.
These are convenient grouping presets, not a claim that every marketplace or printer requires them.
| Family | Common physical sizes | Shape |
|---|---|---|
| 2:3 | 4×6, 8×12, 12×18, 16×24, 20×30, 24×36 in | Tallest of the common inch presets here |
| 3:4 | 6×8, 9×12, 12×16, 15×20, 18×24 in | Middle portrait ratio |
| 4:5 | 4×5, 8×10, 12×15, 16×20, 20×25 in | Squarer portrait ratio |
| 11:14 | 11×14, 22×28 in | Distinct frame family |
| A-series | A5, A4, A3, A2, A1 | ISO paper proportion (1:√2) |
300 DPI example
An 8×10 inch print at 300 DPI needs 2400×3000 pixels. RatioGuard computes this from the physical size rather than using a hard-coded image recommendation.
Crop math
When source and target ratios differ, RatioGuard keeps the largest rectangle with the target ratio that fits inside the source. The crop-loss percentage is based on pixel area removed from that source rectangle.