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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

  • When you say 9.600, do you mean 9 and 6/10 or do you mean 9 thousand 6 hundred? – Joe May 22 '15 at 6:31
  • I mean 9600 nine thousand six hundred – Gabkano May 22 '15 at 12:42
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    In the U.S and U.K., commas are used in groups of thousands, but in most other countries, decimals are used instead. The decimals were technically fine, FWIW. – digijim May 22 '15 at 19:38
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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.

  • Exactly. Think of an inkjet printer as Georges Seurat with a limited number of tubes of paint (often only four) that he's not allowed to mix at all, and tiny brushes of one, two or three sizes that must be dabbed, not stroked. 300DPI (which was actually a common spec back in the early '90s) means you need to see a (full-colour) picture from quite a distance before it looks like a picture rather than like a bunch of dots, and printing an image at 300PPI on a 300DPI (non-giclee) printer would be like converting to a 4-colour (2-bit) GIF. (The whole LPI thing is a red herring here.) – Stan Rogers May 21 '15 at 12:07
  • 2400 / 8 = 600? Did you mean 300? – Janus Bahs Jacquet Dec 18 '17 at 17:52
  • @JanusBahsJacquet yes, good that somebody can calculate – joojaa Dec 19 '17 at 5:05
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OK, I left so many comments in here that I thought I better provide my own answer.

The "300dpi" rule-of-thumb comes from the world of offset printing.

4 color offset printing uses something called a line screen to create a halftone pattern of evenly spaced, but different sized dots.

Offset printing can typically print up to 2400 dpi or even much higher. However, that would be only when you're using 100% of a color--so there'd be no dots. So for text and flat line art, you would want to send an image at that resolution. This is usually handled by simply being a vector image.

For photos, however, because they are continuous tone, to print all the color variations of a photo, they have to turn it into a halftone, and the process of turning it into a halftone means it only needs a certain amount of data, that being typically 300ppi. You can certainly send a 600ppi image to the printer, but you likely won't notice any difference when printed due to the conversion to a halftone.

Example of a halftone image:

enter image description here

Now, all of the above refers to commercial offset printing. Inkjet printing is quite a bit different. Most ink jet printers use stochastic printing. Instead of a halftone of evenly spaced but different sized dots, stochastic printing uses all the same sized dot (very small) and varies how many it puts down in each area.

Because of that, high-end ink-jets can print photos much better than most offset printing can. And, because of that, you can often send much higher resolution photos to the printer and see a difference.

As for why this printer has a different resolution in each direction, that's due to the mechanics of the printer. Many ink jet printers can print in a higher density in one direction than the other.

Example of a stochastic image:

enter image description here

(Both sample photos are taken from this pretty good overview of how ink jet printing works: http://www.thetonesystem.com/inkjet_basics.html )

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You can print at higher than 300 DPI. Usually people will suggest you print at 300 DPI but that doesn't mean you have to.

Printer resolution is expressed in DPI. 9600 X 2400 DPI is the printer resolution. The first term (9600) is very important when looking at resolution, whereas the second number (2400) is critical for highest quality as it refers to how the ink jet head actually pus the ink droplets down in the second dimension of printing. Since printing makes a 2 dimensional print, the second number fills in the ink in the second direction. 9600X2400 is your printers maximum quality, uses the most ink, and takes the longest amount of time. You can print at lower printer resolutions to increase the speed of your print and also save ink. There does come a point, however, where the quality of the print will deteriorate and be unacceptable. Normally, you will select the quality of the print in your printer settings when you select the paper type and quality setting.

Printers DPI

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I need ultra high resolution printing, and so I have devised methods of measuring the output of these printers. I have measured the resolution of all my Canon 9600 dpi printers and found that the true full colour resolution is almost exactly 1000 dpi in all cases. I think that the 9.6x drop in resolution is to do with the matrix needed to get the colour. i.e. they create the full colour from combining the inks over an area 9.6 x (4.8 or 2.4 ~ the resolution in the other direction) x the size of the picoliter droplet. Or: That the "step" of the printer is 1000 dpi, and the 9600 is only refering to the minimum dot size from a picoliter of ink.

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    Oh. It would be interesting if you share us a glimpse on how measure the final resolution. – Rafael Nov 17 '16 at 12:59
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End-user printers use the term "resolution" to mean width and weight.

So in that example, it means the printer will print 9,600 pixels wide and 2,400 pixels tall.

Yes.. it's not standard if you actually work in professional design production. The figured are dumbed-down for mom and pop Smith trying to print the photos of their grandkids from their digital camera which states it takes photos at "8,00dpi x 1200dpi". Is the whole use this way wrong? Absolutely! Do manufactures care? Nope. They just want to sell printers.

As an industry many digital manufactures have never bothered to actually try and educate the public to the level understanding used in professional circles

  • but why do they write dpi at the end? Isn't that a wrong unit there? – Gabkano May 20 '15 at 19:47
  • See my edit @Gabkano – Scott May 20 '15 at 19:56
  • ok that means it can print up to a resolution of digital 9600x2400px by x dpi? – Gabkano May 20 '15 at 19:58
  • The spec sheet footnotes the number 9600 and says "Ink droplets can be placed with a minimum pitch of 1/9600 inch" which sounds like 9,600 dpi ignoring dot gain etc. – Yorik May 20 '15 at 20:28
  • @Scott I don't think that's correct. This is actually referring to print density...not total dimensions. – DA01 May 20 '15 at 21:57
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Nop, nop.

You are confusing dots (tiny droplets of ink) with pixels.

Dots per inch = how many tiny droplets of ink are in a linear inch.

Pixels per inch = The amount pixels of information you will send in a specific phisical print.

I always thought even professional printers only print 300 dpi.

This should be: 300ppi. But that is not entirley true. Some art books are printed using for example 400 ppi or more.

The printer claims to have droplets of 1pl. This is:

1 (ml) = 1/1,000 liter.

1 (ul) = 1/1,000,000 l

1 (pl) = 1/1,000,000,000,000 l

  • I know the difference between the units and that's why I asked the question, because there can't be 9.600 x 2.400 dots per inch, as far as I know... – Gabkano May 20 '15 at 19:49
  • Yes it can. But some printers can use an interpolation method, that is the priner head passes twice on the same spot, puting more dots on an area. – Rafael May 20 '15 at 19:53
  • but wouldn't it than has 23.040.000 dots per inch, if you calculate the value – Gabkano May 20 '15 at 19:55
  • That is square units. But normally you don't use square units. – Rafael May 20 '15 at 19:56
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    That is a diferent question that should not be answered in the coment section. But basicly: 200ppi in photographic output and 300ppi on a comercial print. Thoose 300ppi will be converted to 150 lpi. I'm preparing a tutorial which I´ll probably link later... – Rafael May 20 '15 at 20:20

protected by Community Dec 18 '17 at 10:29

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