Screen mesh to LPI calculator halftone chart

The studio and this calculator use 4.5, then round to the nearest 5 LPI and keep the result between 20 and 65. That gives 20, 25, 30, 35, 45, 50 and 65 LPI across the seven common meshes. The exact quotient is shown to one decimal so you can see how close a mesh sits to the next step.

305 mesh is the one case where rounding is not the end: 67.8 rounds to 70, which is above the 65 LPI ceiling, so it stays at 65. Shirts rarely benefit from more than 65 LPI anyway; the fabric texture is coarser than the screen.

Thread diameters are typical PET monofilament values (the 34-100, 43-80, 49-70, 61-64, 77-55, 90-48 and 120-34 designations in Sefar PET 1500 style mesh tables). Your supplier datasheet wins. The 5% dot is the uncompensated 5% tone at the recommended LPI; it must stay above 1.5 × the thread.

A dot of 1.5 thread diameters is wide enough to bridge one thread and grip the opening on each side. At 156 mesh the thread is 64 μm, so the limit is 96 μm and a 5% dot at 35 LPI (183 μm) is safe. At 305 mesh the thread is only 34 μm, which is why fine mesh can carry dots half the size.

Dot gain compensation makes the smallest film dot smaller. With 15% compensation and a 5% highlight clip, the 156 mesh film dot drops from 183 μm to 146 μm — still safe. The studio's preflight always uses the compensated dot, which is the one that is actually on the film.

Mesh count is threads per inch; the thread diameter decides how much of that inch is open. A 156 mesh woven from 64 μm thread leaves 99 μm openings, while the same count in a thicker thread leaves less open area, holds less ink and needs larger dots to stay anchored.

That is why the limit in this calculator is tied to the thread, not to the count. If your datasheet lists 156-71 instead of 156-64, the wash-out limit rises from 96 μm to about 107 μm, and the 5% dot at 35 LPI still clears it with room to spare.

Dual-cure and photopolymer emulsions differ in exposure speed and how sharply they resolve fine edges, but mesh makers publish no single factor that turns that into an LPI change. The studio records the emulsion in the preflight, the settings sheet and the film header, and uses the same Mesh ÷ 4.5 and 1.5 × thread rules for both.

Your exposure test is where the emulsion shows up: a fast photopolymer may hold the 10% dots on the strip one step earlier than a dual-cure on the same mesh.

Highlight-heavy art

Fades and skin tones need small dots, so choose 196–230 mesh at 45–50 LPI on light shirts.

White underbase on black

110–156 mesh lays down enough white to cover; keep it at 25–35 LPI.

Glitter, shimmer, puff

86 mesh at 20 LPI or no halftone at all; the particles will not pass a finer mesh.

CMYK process

305 mesh at 55–65 LPI with a thin, hard emulsion and low squeegee pressure.

Thread diameters here are typical PET monofilament values. Mesh makers sell the same count with different threads, so read the thread size off your supplier's datasheet and use the halftone generator preflight, which applies the 1.5 × rule for you. The film positive guide covers what happens after the mesh is chosen.