What is HP PhotoREt printing technology?
HP PhotoREt technology is a process of layering multiple drops of ink in each dot to produce photo realistic printed output. This technology has been incorporated into HP's Colorsmart driver software.
HP has created four versions of the PhotoREt technology. The difference between these versions is covered below, as well as the difference between conventional Inkjet technology and HP PhotoREt.
HP PhotoREt and color layering compared to conventional Inkjet technology
Many people believe that dpi is the single most important factor in print quality. In reality, there are two ways to obtain photo-quality: increase the dots per inch (dpi) or increase the levels of color available. HP PhotoREt Color Layering technology uses more color levels to deliver higher quality printing without the disadvantages of higher dpi.
HP’s newest Inkjet printers use small ink drops that are much smaller than those of previous HP printers. This small drop size, combined with extremely precise algorithms, allows the cartridge to place up to 32 drops of ink on a single pixel (up to 19,200 drops of ink per inch), creating more colors per printed dot (pixel). The result is a color palette many times greater than conventional Inkjet printers, finer color control, faster printing, and improved image quality, even on plain paper.
Standard color Inkjet printers place up to two drops of ink per dot. Using the four basic colors of ink and two drops of ink per dot, the typical Inkjet printer produces up to eight different colors per dot. Half toning creates more color shades. Half toning is a process that creates new shades by placing colored dots close together so when viewed from a distance, these dots appear to blend and create a new color. To achieve photo quality, these printers must place more dots per inch. Refer to the images below.
Many high dpi printers deliver optimal color output only on expensive, coated papers. That is because plain paper soaks up ink like a sponge, causing ink to spread unpredictably and paper to buckle from excess ink.
HP PhotoREt Color Layering technology solves both these issues by using smaller ink drops, and by placing those drops more precisely. These small dots visually blend together to create richer colors, smoother gradations, and cleanly defined color boundaries on any kind of paper.
Files at higher dot per inch settings are much larger than those at lower settings. Please refer to the following example for a photograph in the table below:
|Graphic file dpi setting||File size|
|150 dpi||2.2 MB|
|300 dpi||8.7 MB|
|600 dpi||35.0 MB|
|1200 dpi||139.9 MB|
Increasing dpi means sending more information to the print head, which in turn means slower print speeds and larger file sizes. In contrast, HP's PhotoREt Color Layering technology creates small file sizes because its multi-drop per dot method creates accurate color with fewer dots-per-inch. The result is photo-quality color without the wait.
Photo Quality as good or preferable to a traditional photograph is achieved through HP's next generation PhotoREt IV Precision Technology. PhotoREt IV accurately places the highest number of tiny drops at the highest firing frequency of any Inkjet printer with no compromise in speed. The table below shows how HP PhotoREt IV compares to older HP PhotoREt technologies.
|Photo REt||PhotoREt II||PhotoREt III||PhotoREt IV|
|Number of ink colors||6||4||4||6|
|Drop volume||50 pl or 35 pl||10 pl||5 pl||4 - 5 pl|
|Drops per dot||4||16||29||32|
|Levels of shades of color||4||13||17||289|
|Number of colors possible without half toning||48||650||3,500||Over 1.2M|
In 1994, HP developed ColorREt (C-REt) technology enabling HP printers to fire multiple drops of ink per pixel, the first color layering technology. Printers that are C-REt capable use the C51641A color cartridge. C-REt improved color quality by decreasing the ink drop size to get more dots in a pixel. This process enables the printer to use up to four drops of ink per pixel, with different drop combinations. By increasing the drop combination of color ink, C-REt technology produces more intense color, as well as smooth, gradual halftones and dithering patterns.
C-REt technology produces about 30 distinct colors per pixel.
The original PhotoREt Color Layering technology made use of an optional photo ink cartridge (C1816A) inserted into the black cartridge slot to achieve an increased level of ink layering. HP PhotoREt is capable of placing five drops (about 30 - 35 picolitres per drop) of ink per dot. Each cartridge has 48 ink nozzles.
HP PhotoREt II
In 1997 HP introduced the PhotoRET II technology that did not require a separate photo cartridge. HP PhotoRET II printers use the C1823D cartridge (except for the HP Business Inkjet models). HP printers with PhotoREt II Color Layering technology place extremely small (eight - ten picolitres), precise ink drops on the page. In addition to producing small, round drops, PhotoREt II places more drops in each dot. By layering multiple color drops within a single dot, PhotoREt II printers require fewer dots to create accurate color, resulting in better image quality and faster printing.
HP's PhotoREt II printers mix more color shades by layering up to 16 drops of ink per dot to produce many color shades per dot, without half toning.
HP PhotoREt III
HP's PhotoREt III was released in 2000 and is available with products using the HP C6578D ink cartridges (except for the HP Business Inkjet models). Photo Quality as good or preferable to a traditional photograph is achieved through HP's next generation PhotoREt III Precision Technology. PhotoREt III accurately places the highest number of tiny drops at the highest firing frequency of any Inkjet printer with no compromise in speed.
HP PhotoREt III uses tiny drop sizes (five picolitres) and precise algorithms to place up to 29 ink drops per dot, generating a wider range of directly printable colors (over 3,500 colors per dot). HP is the only manufacturer that can fire these tiny drops in all modes and on all papers with no compromise in firing frequency.
HP PhotoREt IV
HP PhotoREt IV uses six ink colors and very tiny drop sizes (four - five picolitres at 18kHz) and precise algorithms to place up to 32 ink drops per dot, generating a wider range of directly printable colors (over 1.2 million colors per dot). This allows up to 289 levels of shades of color to be produced rather than the one - eight shades of printers not using PhotoREt technology. The drop size is so small that it is nearly invisible to the human eye.
Any HP product that can utilize the HP 58 ink cartridge is PhotoRET IV capable. PhotoREt IV capable products print at PhotoREt III capabilities when the HP 56 black ink cartridge is installed instead of the optional HP 58 photo ink cartridge.