Colour Layering Technology (PhotoREt)
What is it?
In 1994 HP developed ColorREt (C-REt) technology - also known as HP's Colour Layering Technology and HP PhotoREt printing technology. After this time HP went on to produce a further three generations (PhotoREt II (1997), PhotoREt III (2000) and we currently stand at PhotoREt IV).
This is HP's exclusive printing technology which is a process of layering multiple drops of ink in each dot to produce photo realistic printed output. Multi layering technology uses the basic CMYK palette to achieve a much broader range of printable colours.
Colour layering allows the printers to output the highest quality photos without sacrificing print speed and combines HP developed hardware, firmware and software advancements. HP use small ink drops that are much smaller than those of previous HP printers. This small drop size, combined with extremely precise algorithms, allow 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 colours per printed dot (pixel).
How does it differ from dpi (dots per inch)?
Most people think that dpi is the single most important factor in print quality. In reality however, there are two ways to obtain photo-quality:
- increase the dots per inch (dpi) or
- increase the levels of colour available.
HP PhotoREt Colour Layering Technology uses more colour levels to deliver higher quality printing without the disadvantages of higher dpi. Many high dpi printers deliver optimal colour output only on expensive coated papers. This is because plain paper soaks up ink like a sponge, causing ink to spread unpredictably and paper to buckle from excess ink.
HP solves both of these issues by using smaller ink drops and by placing those drops more precisely. The small dots then visually blend together to create richer colours, smoother graduations and cleanly defined colour boundaries on any kind of paper.
Files at higher dot per inch settings are also much larger than those at lower settings. Increasing dpi means sending more information to the print head, which in turn means slower print speeds and larger file sizes. By contrast, HP's PhotoREt Colour Layering technology creates small file sizes because its multi-drop per dot method creates accurate colour with fewer dots per inch. The result is photo quality colour without the wait.
What does it do?
By layering ultra small drops within a single dot (e.g. 4 pl for a Designjet 130) the printer is able to produce smoother graduations between tones for virtually grain-free images. The result is also a colour palette many times greater than conventional printers, finer colour control, richer colours, faster printing and improved image quality - even on plain paper.
What are the differences between the various versions of HP PhotoREt?