![]() ![]() This dithered printing process could require a region of four to six dots (measured across each side) in order to faithfully reproduce the color in a single pixel. These disadvantages mean that, despite their marked superiority in producing good photographic and non-linear diagrammatic output, dye-sublimation printers remain niche products, and thus other devices using higher resolution, lower color depth, and dither patterns remain the norm. occasional color registration errors (mainly along the long axis of the page), which necessitate recalibrating the printer to account for slippage and drift in the paper feed system.a wasteful (and, for confidential documents, insecure) dye-film roll cartridge system.lower output speed (a single page requiring three or four complete passes, one for each dye colour, each of which may take more than fifteen seconds-generally quicker, however, than most inkjet printers' "photo" modes).lower spatial resolution (typically 200 to 300 dpi), which can make text and lines look somewhat rough.The exception to this rule is dye-sublimation printers, which can apply a much more variable amount of dye-close to or exceeding the number of the 256 levels per channel available on a typical monitor-to each "pixel" on the page without dithering, but with other limitations: Most printers must therefore produce additional colours through a halftone or dithering process, and rely on their base resolution being high enough to "fool" the human observer's eye into perceiving a patch of a single smooth colour. While some color printers can produce variable drop volumes at each dot position, and may use additional ink-color channels, the number of colours is still typically less than on a monitor. Contrast this to a standard sRGB monitor where each pixel produces 256 intensities of light in each of three channels ( RGB). Higher-end inkjet printers can offer 5, 6 or 7 ink colours giving 32, 64 or 128 possible tones per dot location (and again, it can be that not all combinations will produce a unique result). At each dot position, the simplest type of color printer can either print no dot, or print a dot consisting of a fixed volume of ink in each of four color channels (typically CMYK with cyan, magenta, yellow and black ink) or 2 4 = 16 colours on laser, wax and most inkjet printers, of which only 14 or 15 (or as few as 8 or 9) may be actually discernible depending on the strength of the black component, the strategy used for overlaying and combining it with the other colours, and whether it is in "color" mode. This is due to the limited range of colours for each dot typically available on a printer. The DPI measurement of a printer often needs to be considerably higher than the pixels per inch (PPI) measurement of a video display in order to produce similar-quality output. A laser printer applies toner through a controlled electrostatic charge, and may be in the range of 600 to 2,400 DPI. An inkjet printer sprays ink through tiny nozzles, and is typically capable of 300–720 DPI. A dot matrix printer, for example, applies ink via tiny rods striking an ink ribbon, and has a relatively low resolution, typically in the range of 60 to 90 DPI (420 to 280 μm). The range of DPI supported by a printer is most dependent on the print head technology it uses. A printer does not necessarily have a single DPI measurement it is dependent on print mode, which is usually influenced by driver settings. Up to a point, printers with higher DPI produce clearer and more detailed output. This is caused by the spreading of ink on the surface of the media. DPI is used to describe the resolution number of dots per inch in a digital print and the printing resolution of a hard copy print dot gain, which is the increase in the size of the halftone dots during printing. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |