Editing Printer (computing) (section)

=== Printing speed ===

The speed of early printers was measured in units of ''characters per minute'' (cpm) for character printers, or ''lines per minute'' (lpm) for line printers. Modern printers are measured in ''pages per minute'' (ppm). These measures are used primarily as a marketing tool, and are not as well standardised as [[ISO/IEC 19752|toner yields]]. Usually pages per minute refers to sparse monochrome office documents, rather than dense pictures which usually print much more slowly, especially color images. Speeds in ppm usually apply to [[ISO 216|A4 paper]] in most countries in the world, and [[letter (paper size)|letter]] paper size, about 6% shorter, in North America.