Dots, Lines & Pixels

DPI (dots per inch):
Resolution (dot/spot size on an imaging device).

  • The higher the resolution, the smaller the dot size.
  • The smaller the dot size, the sharper the image.
  • Small dots (high resolutions) are required for high line screens.
  • Common laser printer resolutions are 300, 400, or 600 dpi.
  • Resolutions of 2400 dpi or higher are required for print.
  • DPI is often used interchangeably with PPI (pixels per inch) to describe computer monitor screen resolution or scan resolution.
LPI (lines per inch):
Number of lines or rows of dots in a halftone or screen tint.
  • Standard line screens are 65, 85, 100, 120, 133, 150, 175 & 200 lpi.
  • Small dots (high resolutions) are required for high line screens.
  • 300 dpi laser printers can print a line screen of up to 53 lpi.
  • 600 dpi laser printers can print a line screen of up to 85 lpi.
  • 2540 dpi resolution is recommended for line screens of 150 lpi or above.
General guidelines for selecting line screens:
  • Silk screening on cloth, fabric: 45 to 65 lpi.
  • Photocopy masters: 65 or 85 lpi.
  • Newspaper: 65, 85 or 100 lpi.
  • Quick printing: 85, 100 or 120 lpi.
  • Magazines: 120, 133 or 150 lpi.
  • Commercial printing: 150, 175 & 200 lpi.
PPI (pixels per inch):
Resolution of a scanned image or screen display.
  • The fewer pixels per inch, the less image detail.
  • A Macintosh monitor displays at 72 ppi.
  • A PC monitor displays at 96 ppi.
  • Continuous-tone images for reproduction are typically 300 ppi.
  • Line-art images for reproduction are typically 1200 to 2000 ppi.
  • PPI is often used interchangeably with DPI (dots per inch) to describe computer monitor screen resolution or scan resolution.