半色调效果

源自传统印刷技术，使用点阵创造连续色调的错觉。

使用各种形状的网点、调整大小和间距，创造从复古到现代的效果。

适合复古海报、漫画风格、报纸美学和波普艺术设计。

Moire happens when the dot patterns from two or more colour channels interfere with each other — the wrong rotation angles produce a beat-frequency ripple that looks like fabric watering when viewed at certain distances. This tool defaults to the GATF-RHEM industry-standard CMYK angles (15, 75, 90, 45 degrees for C, M, Y, K respectively), which the printing industry codified in 1949 specifically to minimise moire. Moire still occasionally surfaces in two cases. First, when the source image already contains a regular pattern (a striped shirt, a windowpane plaid, a chain-link fence) — the existing pattern interferes with the halftone screen regardless of angle. Second, when the LPI is too high relative to the source resolution — at 133 LPI on a low-resolution source the screens have no clean tone to map onto and moire emerges from the underlying pixel grid. Fix the first case by picking a non-patterned source or cropping out the patterned region; fix the second by dropping to 85 LPI or 65 LPI on lower-resolution input.

No, and picking the wrong export size is the most common silent failure mode. For magazine, book, or poster offset-press print runs, export PNG or JPEG at 300 DPI with the longest side matching the final print dimension — a US Letter print at 8.5 inches wide needs 2550 pixels on that side, an A4 print at 8.27 inches needs 2480, a 12-by-18 poster needs 3600. The print shop's prepress workflow expects 300 DPI as the source resolution. For digital-editorial layouts on web, Substack, Medium, magazine websites, the export should match the layout's image-slot pixel width — typically 1200 to 1600 pixels wide for hero images, 800 pixels for inline images, and DPI is irrelevant because screen rendering ignores it. The same halftone composition exported at 300 DPI for print and at 1200 pixels for web are visually different because the halftone dot density relative to the viewing pixel grid changes; export both sizes separately rather than scaling one down to the other.