If you’re using a printer to print emails or the occasional photo, the DPI of your printer isn’t an issue. Basic printers have a high enough resolution that most documents will look professional, while photo printers produce fantastic-looking prints. However, if print quality and vivid detail are essential to your work, there’s a lot to know about printer resolution.

Printers print by applying ink or toner to the paper. Inkjet printers use nozzles that spray tiny droplets of ink, while laser printers fuse dots of toner to the paper. The more dots are squeezed into a square inch, the sharper the resulting image. A 600 dpi printer squeezes 600 dots horizontally and 600 dots vertically into each square inch of the sheet. Some inkjet printers have a higher resolution in one direction, so you may also see a resolution such as 600 by 1200 dpi. To a certain extent, the higher the resolution, the sharper the image on the sheet.

Printers can place dots of different sizes, intensities, and shapes on the page, changing the appearance of the final product. Some printers are capable of optimized DPI printing, meaning that their print heads optimize the placement of ink droplets to improve print quality.

Optimized DPI occurs when the paper moves through the printer slower than normal in one direction. As a result, the dots overlap slightly. The final result is rich. However, this optimized technique uses more ink and time than the printer's default settings.