So "print resolution" is meaningless apparently

[Ink stained Fingers]

Referring to PPI's and the capability of the vision system should be measured with an angular measure - e.g. arcminutes or arcseconds - this to make it independent of the viewing distance. You can get to 1 arcminute under special conditions - or even slightly lower - but that's beyond the scope of this thread

https://www.quora.com/What-is-the-highest-resolution-humans-can-distinguish

https://www.scienceinschool.org/article/2016/sharp-eyes-how-well-can-we-really-see/

Much more stuff can be found about 'eye - vision - resolution' if you search for it.

And you can find prior threads here to lenticular printing when you search for it

https://www.printerknowledge.com/search/907657/?q=lenticular&o=date

 

[Tony4597]

No, not at all - the number of nozzles directly impact the printing speed - more nozzles can put more ink onto the paper in a given time. It is a matter of the mechanical construction how the nozzles - the ink ejectors - are arranged - you even can have split nozzle rows for the same color - the 2nd row fits into the gaps of the first row.

Sorry but I have to disagree with you here. You asked about printer native resolution first. The printer has to report its required resolution to the Operating System. In the case of the older professional Epson the driver reports a resolution of 360/720/1440 PPI (newer Epson maybe using 300/600/1200). The report to the OS directly relates to the number of nozzles per inch.
Printing speed is impacted by the print settings you use e.g draft, quality, high quality etc. which dictates the amount of ink droplets per inch and micro stepping of the print head and feed mechanism

This P800 seems to be about the only one with this option - it is a software trick to overcome limitations of the performance of the resizing routine in the driver which creates rather weak/soft output - for reasons of printing speed on lower performance computers.

Epson printers semi pro or pro offer this option but it is not a software trick. It kicks in when a user specifies Finest Details in the Quality Option menu. AFAIK Canon offers similar?
Agreed the resizing routines used by the printer drivers are poor as they use Nearest Neighbour algorithms rather than the more sophisticated resizing algorithms offered elsewhere. This is why it is important if you require optimal print quality that you resample your image to the required PPI prior to sending to the printer so that it does not have to resample to what it requires prior to spooling

Qimage offers something similar - you upscale your image to 1440 dpi, send it to the printer and the resizing routine downscales it to 720dpi, there is in some cases some small gain in sharpness since the software gets along better (a little bit) with downscaling than with upscaling. And all this depends very much of your image content in the first place, but I don't think it makes sense for most pritning jobs.

Qimage offers upscaling of images but according to Mike Chaney it does not get downscaled to 720 PPI.

There can be a real gain in resolving information going above 360 ppi as long as two criteria are met:
1. The image data is at or more than 360 ppi at the required print size
2. That the image content is suitably resolved in the first instance

Images that benefit from higher PPI counts are likely to be those with circles and diagonals typical of this genre is Architectural work where on close examination you may observe jaggies, which would be even more exaggerated by using the printer drivers upscaling methods.

 

[Tony4597]

Sounds like I would want to know the PPI limit of a printer rather than the DPI, however printer manufacturers don't spec this and instead spec DPI, but based on your description I'm not sure why the DPI would ever be quoted in the first place. It doesn't matter if you can place 10 dots within one pixel if their position is basically random. It doesn't correlate with "resolution" which is how it is described in the spec.

No, PPI is not the limit of a printer this is purely a measure of how many pixels your image is made up of in the horizontal or vertical directions. For example suppose you have a 6MP camera and the image resolution is 3000 pixels x 2000 pixels. This will allow you to print a maximum image size of approx 10" x 6.67" @ 300 PPI. Now for this image you will need to choose the quality settings which will determine the number, size and quantity of droplets that will be applied to the paper
You could decide you wanted a bigger print and therefore the PPI on the print would be reduced e.g. @150 PPI your print would become 20" x 13+"

Caveat: Sending less or more than the printers required PPI resolutions results in the image being resampled by the print driver to what it needs.

The lenticular lens sheet has 50 lines per inch. Each line is a pixel, but it will be divided between 10 different images corresponding to 3D angles. So I need at least 500PPI assuming the pixels drawn are perfect, but since they are not I need even higher resolution to ensure that that the 3D transitions look smooth.

May I ask your source for assuming 500PPI?
This source suggests different https://parallaxprinting.com/lenticular-checklist

RESOLUTION
150 PPI. Source images can be surprisingly low resolution and still produce high quality output. This is because lenticular prints are made from many individual images and its the combined pixel dimensions that count. For smaller images (20x20) 150 PPI is a good target and large images can be produced with as little as 100 PPI. Files saved at high resolutions do not improve the quality of the final print.

 

[Ink stained Fingers]

The printer has to report its required resolution to the Operating System.

the transmited resolution (dpi) does not convey any information how many nozzles are active in the printhead, that's a separate value.

Qimage calls it 'Overdrive' sending 1440dpi pixel data which the Epson driver downscales to 720dpi. But yes - high res data needs to be in the original image file in the first place.

But all this does not get Epson - or Canon - printers to print at the required 500dpi resolution for the lenticular images.

 

[Tony4597]

the transmited resolution (dpi) does not convey any information how many nozzles are active in the printhead, that's a separate value.

Sorry, but I am not clear on what you mean about the transmitted resolution (dpi).
The resolution transmitted from the image data in our editing software to the driver is measured in PPI and as such has zero knowledge of printer requirements without us intervening or just allowing the printer driver to interpolate to its requirements.

So that it is clear what I am saying to all
DPI refers to the dots laid down by the printer driver. PPI is the resolution of the image not related to DPI directly.

Qimage calls it 'Overdrive' sending 1440dpi pixel data which the Epson driver downscales to 720dpi. But yes - high res data needs to be in the original image file in the first place.

But all this does not get Epson - or Canon - printers to print at the required 500dpi resolution for the lenticular images.

IF, you need an image file resolution of 500 PPI for Lenticular prints then it seems you have two choices:
1. If the native file resolution is or exceeds 500ppi then you may send your image as is or ideally upsample to 720 ppi so that the printer driver does not have to upsample - optimal data
2. If the native resolution is below the 500 ppi requirement then you would need to upsample to either exactly 500 ppi and let the driver do its thing or ideally upsample yourself to 720 ppi

 

[Ink stained Fingers]

In the case of the older professional Epson the driver reports a resolution of 360/720/

Sorry, but I am not clear on what you mean about the transmitted resolution (dpi).

the driver reports / transmits a particular resolution value - where is the conflict ?

My WF2010W reports a resolution of 720dpi and prints with 3x59 nozzles for the colors. The ET-8550 runs with 180 nozzles per color and does as well 720dpi - and runs faster - with more nozzles, the nozzle row with 59 nozzles is just shorter than a nozzle row with 180 nozzles - with the same dpi of 720.

But all that does not get the user to an eff. resolution of 500dpi.

 

[Tony4597]

the driver reports / transmits a particular resolution value - where is the conflict ?

No conflict it was just unclear if you were referring to PPI or DPI in your post. Now that you have clarified driver reports I understand

But all that does not get the user to an eff. resolution of 500dpi.

500dpi or 500ppi?
Effective resolution in the image data (PPI) or in the print driver (DPI)?

 

[andrew_barrette]

No, PPI is not the limit of a printer this is purely a measure of how many pixels your image is made up of in the horizontal or vertical directions.

This is not "pixels per inch", it's just pixels. I need the pixels printed on paper at a certain density. What to call pixel density? Pixels per inch seems reasonable to me. PPI

For example suppose you have a 6MP camera and the image resolution is 3000 pixels x 2000 pixels. This will allow you to print a maximum image size of approx 10" x 6.67" @ 300 PPI. Now for this image you will need to choose the quality settings which will determine the number, size and quantity of droplets that will be applied to the paper

Now I know that DPI refers to the number and density of droplets which affects the quality of the color mixing, but I don't really care about that right now. Right now I am struggling to print at high pixel density

Caveat: Sending less or more than the printers required PPI resolutions results in the image being resampled by the print driver to what it needs.

I'm not resampling anything. I want a print of a certain size and ppi. I generate an image that is exactly the right number of pixels. No resampling necessary...however now I have to assume the printer is downsampling even though I'm not asking it too. It only has "Normal" and "High" quality settings, so not much I can do there apparently without learning how to write printer drivers, but in reality it's more complicated than that as printing at smaller scales eventually requires you to account for various additional things like vibration isolation.

May I ask your source for assuming 500PPI?
This source suggests different https://parallaxprinting.com/lenticular-checklist

The lenticular lens sheet is 50 lenses per inch. I have 10 cameras mounted in a row that take 10 images from different angles. The images are spliced together so that each lens contains a sliver of each image. So simple math would give 500 pixels per inch. I can always use fewer cameras so that I will have more pixels per sliver within each lens, but then the 3D transition looks more discrete, less smooth. The only way to make it look nicer is to print slivers with more precise/cleaner edges. Currently, at the scale of the slivers, the edges look like rough ink splatter as you can see in the microscope images that I posted.

I figure I just need a printer with better resolution, but it seems that printer manufacturers don't actually care to spec their resolution beyond what people can see, which is unfortunate for applications where microscopic print quality is important.

 

[Ink stained Fingers]

So simple math would give 500 pixels per inch.

That is an resolution you won't get with typical inkjet printers , the question is how much a degradation to 300 pixels per inch is still accepable or terribly looking already - is there any test about all this ? Are there other lenticular films available with a lower lens count - e.g. 40 / inch?

printer manufacturers don't actually care to spec their resolution beyond what people can see, which is unfortunate for applications where microscopic print quality is important.

I think your requirements are so much covering a niche market so that there is no interest by the printer manufacturers to support such business with an inkjet printer specifically designed for such job.

 

[Tony4597]

This is not "pixels per inch", it's just pixels. I need the pixels printed on paper at a certain density. What to call pixel density? Pixels per inch seems reasonable to me. PPI

Yes PPI is industry standard

.....

I'm not resampling anything. I want a print of a certain size and ppi. I generate an image that is exactly the right number of pixels. No resampling necessary...however now I have to assume the printer is downsampling even though I'm not asking it too. It only has "Normal" and "High" quality settings, so not much I can do there apparently without learning how to write printer drivers, but in reality it's more complicated than that as printing at smaller scales eventually requires you to account for various additional things like vibration isolation.

I only mentioned resampling as if you do not produce an image file that equates to your required PPI at the final size print size the print driver will do this for you which may be sub optimal.
The printers Normal and High quality settings relate to printer DPI and is selected in the printer driver to control how fine grain the dots pattern will be in the final print

The lenticular lens sheet is 50 lenses per inch. I have 10 cameras mounted in a row that take 10 images from different angles. The images are spliced together so that each lens contains a sliver of each image. So simple math would give 500 pixels per inch. I can always use fewer cameras so that I will have more pixels per sliver within each lens, but then the 3D transition looks more discrete, less smooth. The only way to make it look nicer is to print slivers with more precise/cleaner edges. Currently, at the scale of the slivers, the edges look like rough ink splatter as you can see in the microscope images that I posted.

This type of application is beyond my comfort zone. FWIW I would have thought that 10 cameras should of provided enough pixel information, however I am sure there is a lot more to this process than I first thought

I figure I just need a printer with better resolution, but it seems that printer manufacturers don't actually care to spec their resolution beyond what people can see, which is unfortunate for applications where microscopic print quality is important.

What do the commercial labs use equipment wise?
Do they quote in PPI or LPI (Lines per inch). If LPI then a rough guide is that LPI is roughly half the PPI of an image