Convert Dots per pica to Lines per inch

Convert Dots per pica (dot/pica) to Lines per inch (lpi) instantly and accurately.

Conversion Formula

lpi = dot/pica × 6

About Dots per pica

The dot per pica (dot/pica) is a typographic resolution unit linking printer DPI to the pica - exactly 1/6 inch in the PostScript standard (Adobe, 1985). A 72 DPI Macintosh screen placed exactly 12 dots per pica (1 dot per point); a 300 DPI LaserWriter placed 300/6 = 50 dot/pica, providing 50-level halftone cells per pica. High-end digital imagesetter platemakers: Agfa Selectset Avantra 45 at 3600 DPI = 600 dot/pica; modern 2400 DPI proofers produce 400 dot/pica. Desktop publishing software - Adobe InDesign, QuarkXPress, Affinity Publisher - defaults to pica+point rulers (e.g., 4p6 = 4 picas 6 points = 0.75 inch), making dot/pica a natural precision unit for typographic rasterisation quality assessment. 1 dot/pica = 6 DPI = 6 PPI (since 1 pica = 1/6 in). 1 dot/pica = 6 PPI = 15.24 dot/m.

About Lines per inch

The line per inch (lpi) is the standard unit of halftone screen frequency in offset, flexographic, gravure, and screen printing. Each halftone cell varies in dot size to simulate grey tones; a 150 lpi screen on a 1200 DPI printer allocates 1200/150 = 8 printer dots per cell row, giving an 8×8 = 64-level grey matrix. Industry benchmarks: newsprint 85-100 lpi; magazines 133-175 lpi; fine-art offset 175-200 lpi; screen printing (textiles) 35-65 lpi. Rule of thumb: required DPI ≥ 1.5 × lpi for acceptable AM halftone; ≥ 2 × lpi for high quality - so 150 lpi offset needs at least 300 DPI raster data. As a dimensional quantity, 1 lpi = 1 PPI = 1 DPI; lpi designates screen frequency in print. 1 lpi = 1 PPI = 2.54 lpcm.

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