Halftones: line count, angle, dot shape

Line count (LPI). Common guidance is a mesh count of about 4–5 times your LPI. PrintFilmReady divides mesh by roughly 4.5, which gives about 24 LPI on 110 mesh, 35 on 156 and ~50 LPI on 230 mesh (mesh ÷ 4.5–5, about 46–51). ScreenPrinting.com suggests 230 mesh for 45 LPI and 280 for 55 LPI and up. These rules land on slightly different numbers. Treat them as starting points and test on your own press.

Angle. The maker of AccuRIP recommends 22.5° for every screen, CMYK included, to avoid moiré with the mesh. For CMYK on clothing, a common screen-printing set at 55 LPI is Cyan 22.5°, Magenta 52.5°, Yellow 82.5°, Black 82.5°, with white and spot colors at 22.5°. These sit 7.5° off the usual press angles so the dots stay off the mesh threads (yellow can share black’s angle because it’s so light). The 15°/75°/0°/45° set you’ll see elsewhere comes from offset printing on paper and is more likely to cause moiré on mesh. Fresener uses 55 LPI at 25° for index underbases.

Dot shape. Round dots resist moiré but can jump more than 15% in the midtones. Elliptical and diamond dots reduce that midtone jump but are more prone to moiré (Screen Printing Magazine).