Convert Dots per point to Dots per centimetre

Convert Dots per point (dot/pt) to Dots per centimetre (dpcm) instantly and accurately.

Conversion Formula

dpcm = dot/pt × 28.34645669

About Dots per point

The dot per point (dot/pt) expresses output resolution relative to the PostScript point - exactly 1/72 inch, codified by Adobe in the PostScript Language Reference (1985). The Apple Macintosh 128K (1984) ran its built-in CRT at exactly 72 DPI, placing 1 dot per point - an intentional WYSIWYG design: a 12-point character on screen measured 12 pixels tall and printed at 12 points on the Apple LaserWriter. Device resolution milestones: Apple LaserWriter (1985) 300 DPI = 300/72 ≈ 4.17 dot/pt; HP LaserJet 4 (1992) 600 DPI ≈ 8.33 dot/pt; Linotronic 300 imagesetter (1985) 1270 DPI ≈ 17.64 dot/pt; Agfa Selectset 5000 at 2400 DPI = 33.33 dot/pt. TrueType and OpenType font hinting instructions align outline points to raster device pixels at the current dot/pt ratio. The CSS pt unit equals the PostScript point: 1 CSS pt = 1/72 CSS in = 4/3 CSS px at 1 dppx. 1 dot/pt = 72 DPI = 72 PPI.

About Dots per centimetre

The dot per centimetre (dpcm) is the metric equivalent of DPI, defined as a CSS resolution unit in the W3C CSS Images Level 3 specification alongside dpi and dppx. A 96 DPI reference screen (CSS Media Queries Level 4 reference device) corresponds to 96/2.54 ≈ 37.795 dpcm. ITU-T T.4 (Group 3 facsimile, 1980) defines scan line density in metric units: standard resolution 3.85 lines/mm = 38.5 dpcm; fine resolution 7.7 lines/mm = 77 dpcm. ITU-T T.85 (JBIG compression) standardised these metric resolutions for cross-border interoperability. ISO 216 A4 scanned at 77 dpcm fine fax resolution yields 1617 pixels across page width. The CSS specification recommends dppx over dpcm for screen media queries, reserving dpcm for print stylesheets targeting metric-resolution printers. 1 dpcm = 2.54 DPI = 2.54 PPI exactly (since 1 in = 2.54 cm). 1 dpcm = 0.1 dot/mm.

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