How can a print have a resolution of 9600 x 2400 dpi?

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While reading about the CANON PIXMA MG5150 printer (http://www.canon.de/printers/inkjet/pixma/pixma_mg5150/), there was a stated print resolution of 9600 x 2400 dpi. How is this value meant here, since I always thought even professional printers only print 300 dpi.

Of course they could just mean resolution without dpi, which would make sense, but why do they then write about dpi?

Thank you,
Gabriel/Gabkano

Answer

Printed medium works differently form screens. Screens have 3 color elements very close to each other. Each element is capable of different color intensities. Printers on the other hand produce dots of limited number of colors usually 4 colors, but can be more and have 3-4 mid tones or so. To show mid tones it has to spread the dots around. The end result is that the accuracy of each dot is quite irrelevant for the picture as many dots produce what one pixel produces on a screen.

Screens and other continuous media measure PPI (Pixels Per Inch) while printers measure DPI (Dots Per Inch), although PPI is quite commonly mislabeled DPI. These 2 metrics measure completely different things. So when somebody says the printer prints at 600 dpi you prepare a image at 150+ PPI if they say its 1200 you prepare at 300 and then stay at that because tit becomes unwieldy to go over that, unless you have pixels to spare. If you have a insanely good printer you might go up to 600 PPI.

Dot pattern

Image 1: Dot pattern of a inkjet, image by Jeff Thompson

compare

Image 2: Compare that to a screen and you can see its much much denser

Since the printer needs space for the blending in fact the image is needs about 16 by 16 dot area to represent a color range of 256 levels. In practice the rasters can be interleaved a bit so the number might be 8 or 10. Maybe less with intermediate tones in the cartridges.

So:

2400DPI /8 = 600  PPI
2400DPI /9 = 267 PPI
2400DPI /10 = 240  PPI

Off course here the printer has higher Dpi in the print head axis direction… Most likely the printer works best with something like 300, 450, 600 PPI. Depends a bit of factors that the DPI cant say. Id guess its meant to be a 600 PPI one. So while the numbers sound insanely high you dont use that kinds of resolutions to send to the printer. They have over resolution to compensate for a technical weakness (Its easier to add dots than to mix colors).

estimate

Image 3: Estimate of the actual pixel image the inkjet dot pattern represents, zoomed to match size.

It isn’t obviously this simple but something like this.

TL;DR

Essentially they measure so different things that you can not compare print resolution and screen resolution without considering what the image is.

Attribution
Source : Link , Question Author : Gabkano , Answer Author : Community

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