5760 x 1440 vs. 2400 x 1200 Really?

[Abitconfused]

An Epson P600 printer (13") boasts 5760 x 1440 DPI whereas an Epson PRO-1000 (17") has 2400 x 1200 DPI. But can the eye recognize any difference in a similar print?

[Donald]

Depends. How big is your print? At what distance will it be looked at? How did you size the print for printing? etc.,

[Abitconfused]

Let's say 13" viewed at two feet.

[revi]

Printers, DPI (Dots per Inch, iirc), so print size doesn't matter. Viewing distance does
matter, but at that kind of resolutions you'd see the difference if you are closer than
say 10 cm...

But, those resolutions indicate the number of dots the printer can produce per inch.
I seem to remember something about printers often using dithering to increase the
apparent number of colours they can reproduce. If that's indeed the case, the
resolution in terms of 'image pixels' will be lower (at least half, perhaps even less).

But even an effective resolution of 300 DPI is enough for a print viewed from 30 cm.
(again, we're talking DPI in the print, so final print size is irrelevant).

[DanK]

I don't know the answer, but I think you need to distinguish dots from pixels. If am not mistaken (I print with Canon printers, so I could well be), the native resolution of most Epson printers is 360 PPI, and some have the option of printing at twice that, 720 PPI. Unless I am mistaken, the much larger number of dots listed for printers takes into account the multiple dots the printer uses for each pixel, to get the best color. For example, 1440 DPI for a 13" print at 360 DPI indicates four dots per pixel. If am wrong, someone correct me.

[Manfred M]

+1 to Remco's comment. He is definitely on the right track.

Ink jet printers produce the variable colours by mixing ink from a number of different ink colours; the greater the number of dots, the higher the number of colours that can be reproduced. A printhead that has more dots can create more colours. There are two different operations in play here; one is related to the number of dots on the printhead itself, which determines the amount of ink that the printer deposits as the nozzle carrier is transported back and forth across the page. The other is related to the distance that the platen indexes the paper as it is fed past the printhead. The other variable is the number of discrete colours that are available in the printer itself. The P600 (and my Epson 3880) uses 8 different colour cartridges at a time for printing. The unit has 9 cartidges, two of which are black. Only one black is used at a time, there is one for photo papers and one for matte finish papers

The 2400 x 1200 is what the previous generation of printers (like my Epson 3880), so with the newer generation like the P600 with the 5760 x 1440 pattern, more dots can be deposited in both the direction the printhead moves as well as in the direction the paper advances, so more distinct shades can be produced.

You won't necessarily see any difference in resolution per se as this is dependent on a number of factors including how the ink that is deposited "bleeds" on the paper surface, but you will see more subtle tonality in the final image because the printer can generate more dots.

[xpatUSA]

+1 to Remco's comment. He is definitely on the right track.

Ink jet printers produce the variable colours by mixing ink from a number of different ink colours; the greater the number of dots, the higher the number of colours that can be reproduced. A printhead that has more dots can create more colours.

Struggling with that a bit, but I'm no printer expert. I suppose it's analogous to bit depth in image files?

[dje]

I like to use the terms “dots” and “droplets” where a dot is a little square corresponding to one image pixel** and a droplet is one little squirt of ink from a nozzle. If you are printing at 300 ppi/dpi and the droplet resolution is say 9600x2400, then each dot can be populated by a 32x8 array of droplets. The color of the dot should match that of the image pixel as closely as possible and this is achieved by populating the dot with varying numbers of different color droplets to get the hue right and by leaving some droplet positions blank to get the lightness right (a process called half toning). The more droplets you have the finer the color adjustment. But that is an over-simplified description. Things such as variable droplet size and droplet overlap are also called into play. Quite complex and mostly proprietry,

Dave

** When I say one image pixel I am referring to a pixel in the image re-sized such that it's ppi for a certain size print matches the native dpi of the printer eg 300dpi or 360dpi or 600dpi etc

[rudi]

An Epson P600 printer (13") boasts 5760 x 1440 DPI whereas an Epson PRO-1000 (17") has 2400 x 1200 DPI. But can the eye recognize any difference in a similar print?

Hi Ed, I think you meant : Epson P600 and CANON Pro-1000 ??
I can not speak for a comparison between the two printers. A while ago we compared some prints from an epson sc-p600 printed at 1440dpi and at 5760 dpi, and it was very hard to see any difference between the two.

[Manfred M]

Hi Ed, I think you meant : Epson P600 and CANON Pro-1000 ??
I can not speak for a comparison between the two printers. A while ago we compared some prints from an epson sc-p600 printed at 1440dpi and at 5760 dpi, and it was very hard to see any difference between the two.

The Epson is a 9-ink model and the Canon uses 12 inks, so the Canon should produce a wider gamut and more subtle colours. The Epson prints 13" x 19" paper and the Canon handles 17" x 22" paper, so the capabilities are different there too.

One would have to look at the same image printed on each printer side by side under good light to see the differences, but I would expect that one would see them.

[xpatUSA]

An Epson P600 printer (13") boasts 5760 x 1440 DPI whereas an Epson PRO-1000 (17") has 2400 x 1200 DPI. But can the eye recognize any difference in a similar print?

Indeed "the eye" has to be the determining factor. The average eye can distinguish objects of 1 arc-minute.

https://en.wikipedia.org/wiki/Visual_acuity

Pardon me for introducing angular measure into the comfortable world of so many dpi or ppi.

So all we have to do is translate 5760 x 1440 DPI or 2400 x 1200 DPI into angular measure at some chosen viewing distance and we can see if "the eye" can distinguish a difference or not.

[Manfred M]

Indeed "the eye" has to be the determining factor. The average eye can distinguish objects of 1 arc-minute.

https://en.wikipedia.org/wiki/Visual_acuity

Pardon me for introducing angular measure into the comfortable world of so many dpi or ppi.

So all we have to do is translate 5760 x 1440 DPI or 2400 x 1200 DPI into angular measure at some chosen viewing distance and we can see if "the eye" can distinguish a difference or not.

Ted - great answer, but your assumptions are incorrect. Unlike looking at a screen print or a computer screen, the individual dots are not visible. Look at Dave's response - the individual droplets of ink are smaller than 1/1000th of an inch for event the worst case of 1200 dpi. Depending on the type of ink (in these two printers we are looking at pigment based ink, rather than dye based ones) and the substrate, these inks will "bleed", making them even less distinct.

The issue is about the range of colours that can be reproduced; both discrete shades as well as the gamut boundaries. The two companies take a different approach to getting the colours; Epson uses fewer colours, but a much finer dot pattern to create the colours whereas Canon uses a coarser pattern, but more discrete inks (a red, blue and a finisher). The printhead technologies are quite different as well. Epson has a much finer printhead as it uses ultrasonic frequencies to spray the ink whereas Canon (and HP) effectively "boil" the ink with high temperatures to create a bubble that spatters onto the medium. By not using high heat (in the range of 500 degrees C, I believe), Epson has greater flexibility in how the inks are formulated as they are not subject to high heat. I understand that Epson has an advantage in the blue / greens and Canon is stronger in the reds.

[DanK]

Manfred,

A very informative post. I have been printing for years with Canon dye printers and have been thinking off and on about switching to pigment--not for appearance, but because I would be more comfortable selling the longer-lasting pigment prints. I hadn't yet seen an explanation of this difference between Epson and Canon pigment printers.

Dan

[Manfred M]

Manfred,

A very informative post. I have been printing for years with Canon dye printers and have been thinking off and on about switching to pigment--not for appearance, but because I would be more comfortable selling the longer-lasting pigment prints. I hadn't yet seen an explanation of this difference between Epson and Canon pigment printers.

Dan

Dan the best source of information I have found on print permanance is Wilhelm Research:

http://www.wilhelm-research.com/

Unfortunately as printers are quite proprietary there is little verifiable out in the wild. I believe all three major printer manufacturers use Wilhelm Research to validate their paper / ink longevity data.

Back to a bit of a history on printers lesson. Canon initially developed the ink jet technology. I believe the earliest Canon ink jet printers were branded "bubble jet", because this was effectively how they worked. The ink was heated by the nozzle (I have read that the temperature of the nozzle is nominally 500 °C, ± 5°C. The ink is boiled at that temperature and as the boiling bubble "explodes", it is deposited on the substrate. HP uses very similar technology. My understanding is that the advantages of this technology is that it is quite inexpensive to produce, and in fact the print head can be part of the cartridge and in many printer when you change the cartridge, you also change the print head. The downsides are the heat process does have some variability and there is some droplet scattering inherent in the process. Both dye based and pigment based inks use the same basic process, but the nozzle design is customized to the ink so dye based ink cannot use a pigment nozzle and vice-versa. Both Canon and HP use a 300 dpi print head.

Epson is a bit different. It is part of the Epson-Seiko Corporation and their print heads borrow the piezoelectric technology used in quartz watches. Instead of heating up the ink, ultrasonic frequencies are used to vapourize the ink. This technology is very precise, does not suffer from the ink splatter issues of the heated nozzles, but the print heads are part of the printer and more expensive than the heated nozzle design. The resolution is finer with 360 dpi being the native resolution with Epson printers.

The Epson inks are not subjected to high heats, so the inks are generally regarded as having better colour properties than the Canon and HP ones especially when it comes to metamerism.

Dye and pigment based ink have evolved and their performance properties are getting closer to each other. Dye based inks are slightly more vibrant than pigment based ones, but have a somewhat shorter life. Dyes are more subject to damage (moisture and abrasion) than pigment based inks and pigment based inks are still the main stream in photo print applications.

Ink permanence is excellent, and when properly stored in a dark environmentally controlled space, permanence is measured in the 200 - 300 year range. Unfortunately, prints are not displayed under those conditions, so the theoretical data is a bit optimistic. UV and airborne contaminants are the enemies of permanence, so an appropriate protective coating will double the print life. Mounting the print under plastic or glass have the same effect. Both approaches also reduce sensitivity to airborne contaminants and abrasion damage. Dye based inks are more susceptible to both UV and airborne contaminants than pigment based ones. I have read that HP has the best permanence, Canon is in the middle and Epson is at the low end, but regardless, these inks will outlast any other printing process, including the traditional silver and offset press based products. Print life is also related to paper, so the long print life assumes archival quality, acid free and optical brightening agent (OBA) free paper being used. Cotton based papers outlast papers made from trees. Resin coated papers will yellow over time.

I understand the Epson is the "elephant in the room" when it comes to ink jet photo printers and outsells the other two manufacturers for this specific application.

I hope that this clarifies things a bit Dan.

[xpatUSA]

Ted - great answer, but your assumptions are incorrect. Unlike looking at a screen print or a computer screen, the individual dots are not visible. Look at Dave's response - the individual droplets of ink are smaller than 1/1000th of an inch for event the worst case of 1200 dpi. Depending on the type of ink (in these two printers we are looking at pigment based ink, rather than dye based ones) and the substrate, these inks will "bleed", making them even less distinct.

OOPS - quite right, I was including the ppi setting in my word "translate" and should have expanded on that in my post. Had I been more familiar with the printers involved I could had done better. Thanks for the clarification.

The issue is about the range of colours that can be reproduced; both discrete shades as well as the gamut boundaries. The two companies take a different approach to getting the colours; Epson uses fewer colours, but a much finer dot pattern to create the colours whereas Canon uses a coarser pattern, but more discrete inks (a red, blue and a finisher). The printhead technologies are quite different as well. Epson has a much finer printhead as it uses ultrasonic frequencies to spray the ink whereas Canon (and HP) effectively "boil" the ink with high temperatures to create a bubble that spatters onto the medium. By not using high heat (in the range of 500 degrees C, I believe), Epson has greater flexibility in how the inks are formulated as they are not subject to high heat. I understand that Epson has an advantage in the blue / greens and Canon is stronger in the reds.

You said elsewhere in this thread that they have 300 and 360 dpi print-heads and I take it that those dots are the not the same dots as in 5760 dpi, etc.

So, from my earlier POV of visual acuity, the 300 and 360 numbers (or less if so selected) are what would be translated into angles.

At which point, my earlier post becomes trivial because there will obviously be some distance at which the Canon print will look "better" than the Epson. For example, if those print-head dots (not pico-liter squirts of ink) consisted of a perfect black and white checker-board pattern, then the 300 dpi pattern would have to be viewed closer than the 360.

Classic photography - a "dot" having two separate meaning, it seems . . .

[Manfred M]

The point you seem to have missed Ted is that a "dot" is not clearly defined. There are two levels of dots, one is the small droplet of ink deposited by the print head as it traverses across the width of the paper and the other is defined as the number of these droplets deposited as the platen advances the paper past the print head. There are around 32 of these droplets that are deposited per "dot". These will smear out a bit as they hit the substrate. Even under magnification with a matte paper, I cannot resolve the individual dots on the page, so the visual acuity is somewhat moot.

I agree that the definition of "dot" is NOT clear.

[DanK]

Manfred,

Many thanks for the second informative post. I have looked at Wilhelm research in the past, when I was trying to decide whether I would make do with dye-based inks at the time (yes) and whether I would use non-OEM inks (no). I hadn't gone back to their site to compare Canon to Epson pigment printers.

One of my major concerns is clogging of the print head. I know that you have not had bad luck in this respect, but many other people I know have. In contrast, in all of the years I have been using dye-based Canon printers (4 different models at this point), I have never had a clogged head, even after leaving a printer idle for months. I have read that the manufacturers have made strides in reducing this problem with pigment printers, but I haven't yet seen any comparisons of Canon to Epson in this regard. I print erratically, so it is more of an issue for me than for people who print more regularly.

BTW, I am old enough that I remember printers being called "bubble jet" printers, but I think the ones I encountered at that time were HP.

Dan

[Manfred M]

Dan - on the other hand I had two Canon inkjet printers (dye based) and both were terrible for clogging, even with regular use. It got to the point that I would not even consider a Canon printer when I bought my Epson. I believe / suspect that clogging is more common with the lower end printers than with higher end ones.

I know several photographers who own Epson "pro" = higher end photo printers and their experience is the same as mine with regards to clogging. Like you, I am a sporadic printer and will go months without printing and will then get into a period where I print very frequently.