What is Screen angle?
The rotation angle of a halftone dot grid. In multi-color printing, each color uses a different angle to prevent moiré interference patterns.
In detail
Screen angle is the rotation of the halftone dot pattern relative to horizontal. Standard CMYK angles (75°/15°/0°/45° for K/M/Y/C) are designed so dot grids don't align between channels. Misaligned angles produce dot-rosettes (small flower-like clusters) that the eye blends; aligned angles produce visible moiré (rippling interference patterns). Spot-color screen printing uses 22.5° as the dominant angle and offsets secondary colors by 30° (making 52.5°, 82.5°, 112.5°). Choosing screen angles is largely automated in production software but requires manual review for designs with strong directional elements (stripes, gradients) where standard angles can clash. Standard textile screen angles follow the convention 22.5° (dominant color), 67.5° (offset), 90° (yellow), 45° (magenta) — chosen because adjacent angles separated by ~22-30° produce minimum moiré interference at the dot frequencies textile printing uses. Deviating from these standards risks visible moiré that even careful registration cannot hide.
Example
A four-color screen print of a floral: navy at 22.5°, coral at 52.5°, sage green at 82.5°, gold at 112.5°. The four halftone dot grids interlock at offset angles, producing rosettes the eye blends into clean color rather than moiré stripes.