DPI is an acronym for Dots Per Inch. If a Dye Sublimation printer specifies 300 DPI, it means that for every inch of image there are 300 color dots (or pixels). When an image that is 640 pixels by 480 lines is printed to a 300 DPI Dye Sublimation color printer, the image will be 2.13" wide by 1.60" high. It is assumed that when the image was printed, the "Fit to Page"
wasn't checked in the print driver and no other interpolation of the image was performed in software.

Dots Per Inch on a LaserJet printer will print a black "dot" or no "dot" depending on the image. For the Laser printer to reproduce shades of gray, it relies on a technique called "Dithering". Dithering uses the spacing of the black dots to represent the gray level of a pixel. The closer the spacing of the dots, the darker the pixel. When looking at an image printed on a LaserJet the images appear more realistic when viewed at arms length as opposed to close up.

Example of a grayscale pixel printed on paper by a LaserJet printer