A pixel, or picture element, is the smallest tonal element of a digital imaging or display system. This definition applies to scanners, digital cameras, and most software applications. Describing a pixel becomes much more difficult when discussing monitors and laser printers, since monitors display images by illuminating phosphors, and laser printers print dots.
Dots-per-inch = round dots
Pixels-per-inch = rectangular shapes
Scanners and most applications operate using pixels, and printers operate using dots. In order for a printer to reproduce a photograph, a halftone cell must be created. A halftone cell could be considered the same as a pixel in the context of a printer, although it must be understood that a halftone cell is made up of several rows of dots that are created by the printer laser.
6x6 cell 10x10 cell
600 dpi 600 dpi
-------- = 100 Lpi ---------- = 60 Lpi
6 10
The smaller the halftone cell is, the greater the LPI is, and visa-versa. Also, the larger the halftone cell (matrix) is, the more shades of gray or color can be represent. For example, in the 3x3 matrix, up to 82 different patterns of shading can be generated. If colors are added to a picture (cyan, magenta and yellow), the numbers of different shades or colors within a 3x3-halftone cell would be enormous.
Dots-per-inch = round dots
Pixels-per-inch = rectangular shapes
Scanners and most applications operate using pixels, and printers operate using dots. In order for a printer to reproduce a photograph, a halftone cell must be created. A halftone cell could be considered the same as a pixel in the context of a printer, although it must be understood that a halftone cell is made up of several rows of dots that are created by the printer laser.
6x6 cell 10x10 cell
600 dpi 600 dpi
-------- = 100 Lpi ---------- = 60 Lpi
6 10
The smaller the halftone cell is, the greater the LPI is, and visa-versa. Also, the larger the halftone cell (matrix) is, the more shades of gray or color can be represent. For example, in the 3x3 matrix, up to 82 different patterns of shading can be generated. If colors are added to a picture (cyan, magenta and yellow), the numbers of different shades or colors within a 3x3-halftone cell would be enormous.
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