Halftone.

A pattern of solid dots and open gaps that the eye reads as tone, used on DTG and DTF to make fades, shadows and textures without semi-transparent pixels. DTF Dallas describes it as larger or closer dots in the dark areas and smaller or wider-spaced dots in the light ones, and dot frequency is counted in lines per inch, LPI. ColDesi starts DTF at 40 LPI, with 25-35 for a vintage look, 45-55 for photos and 30-40 on the white layer; DTF Dallas puts the usual start at 45-65, so the number is a test point, not a rule. Platforms ask for it by name: Printify recommends a halftone gradient on coloured DTG garments in place of a transparent one. The usual mistake is halftoning text, logos and thin lines along with the background, which breaks edges that should have stayed solid. Skip it on DTF and a large solid fill presses as a stiff, plasticky block across the chest.