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HP Color LaserJet 5 and 5M Printers - Printer Technology (Image REt 1200 and Lines Per Inch)

ISSUE: What is Image REt 1200 technology?
SOLUTION: The following information describes Image REt 1200 technology.

Printer Technology

HP Image RET 1200

The HP Color LaserJet 5/5M printers include the new HP Image Resolution Enhancement technology 1200 (Image Ret 1200), which significantly improves print quality. The driving technology behind HP Image REt 1200 is the ability to precisely blend toner with a proprietary toner-on-toner process. The result is millions of solid, pattern-free colors and photorealistic 1200-dpi-equivalent images.

Through accurate color control techniques, HP Image REt 1200 technology lets the printer precisely blend up to four toner colors together--within the space of a single dot--to create a true solid color. Like an artist mixing paints on a palette to get a desired color, HP Image REt 1200 ensures precise color creation by telling the HP Color LaserJet 5/5M printers to "blend" the exact amounts of primary color toner needed to achieve a required shade.

For example, to print a solid, dark orange dot, HP Image REt 1200 blends a small amount of magenta toner with a larger amount of yellow toner and a tiny amount of black toner. If a slightly lighter shade is specified, HP Image REt 1200 precisely adjusts the amounts of magenta, yellow, and black toner accordingly.

Older color printers were forced to create colors by placing them side by side in dithered patterns, and the result was grainy, lower resolution color output. The HP Color LaserJet 5/5M printers with HP Image REt 1200 can place colors on top of each other in precise proportions, and the result is solid, pattern-free colors. With HP Image REt 1200 technology, the HP Color LaserJet 5/5M printers join a new class of color laser printers that produce smooth "continuous tone" print quality.

The benefits of HP Image RET 1200

  • Photorealistic image quality: HP Image REt 1200 creates images that are 1200 dpi-equivalent. Images printed on the HP Color LaserJet 5/5M printers show a high level of detail, and color transitions are smooth and natural.

  • Millions of solid colors: Graphics are sharp and crisp. Colors are pattern-free--without the dithered, lower resolution look of older color printers.

  • Office standard HP LaserJet quality text: crisp and readable, in black or any color.

Lines per Inch

Lines per inch (lpi) is a common method of describing the amount of detail that can be rendered by a particular halftone. In the commercial printing industry, printers know the maximum number of lines per inch of which a particular paper stock and press are capable, and a color separator knows the minimum number of lines that are required to render the detail in a particular image. In commercial printing, halftones range from 75 lpi or less (for newsprint printed on a high-speed web press) to 200 lpi (for the finest magazines printed on coated stock, such as National Geographic). The eye is unable to distinguish between a halftone and a continuous tone image when the halftone is 250 lpi or above.

Lpi is the maximum number of lines that can be drawn in one inch with white space between each line. The higher the lpi, the sharper an image will be. The HP Color LaserJet 5/5M printer offers users significant improvements in lpi, which produces higher definition and more colors.

Images that are greater than 200 lpi are considered to be photographic quality. The HP Color LaserJet 5/5M printers are capable of producing high definition color output at up to 300 lpi, giving the appearance of 16.7 million solid colors using standard memory in the printer.

Lpi affects output resolution because it determines the size of a halftone "cell" (the boundary of a digital halftone dot). For example, halftone cell size gets smaller as lpi goes from 50 to 100 to 300 lpi. Smaller halftone cell sizes produce finer definition. In other words, less halftoning (or dithering) is visible at higher lpi settings. At 300 lpi, the eye cannot see any visible dot structure.

To illustrate how lpi affects output, compare the HP Color LaserJet 5/5M printer to the list of approximate lpi resolutions from various sources.

Source
lpi
HP Color LaserJet 5/5M printer
100, 150, 300
HP LaserJet 4V printer (monochrome)
106
HP Color LaserJet printer
55
Newspaper
65-85
Photograph
>200

The tradeoff for higher lpi and smaller halftone cell sizes used to be the number of colors that could be produced (at smaller halftone cell sizes, fewer colors could be produced). This was true before the HP Color LaserJet 5/5M printer.

With HP's exclusive technology, the HP Color LaserJet 5/5M printer produces the appearance of 16.7 million solid colors at 300 lpi. Furthermore, this new technology does not require excessive amounts of processor power or memory.

The combination of higher lpi and HP technology allows the HP Color LaserJet 5/5M printer to print with extremely high definition at an affordable price.

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