Printer quality

[DeanChriss]

An inkjet printer has a max resolution of 2880 dots per inch. The resilution of the digital file needed is then 730 pixels per inch.
How to relateren this with displays? Is the dots per inch the measure or the pixels per inch?

I think in this context we're looking at pixels per inch (PPI), not the density of the single-colored dots on a print or R, G, and B sub-pixels on a monitor.

[Bart_van_der_Wolf]

An inkjet printer has a max resolution of 2880 dots per inch. The resilution of the digital file needed is then 730 pixels per inch.
How to relateren this with displays? Is the dots per inch the measure or the pixels per inch?

The 2880 dots is dot placement accuracy, droplets, the fineness of the dithering pattern.
Pixels Per Inch (PPI), 360 or 720 PPI for Epson printers, is what determines output size.
For 720 PPI, the "finest details" option must be used, otherwise the printer will down-sample to 360 PPI.

Cheers,
Bart

[kers]

One thing that needs to be mentioned with displaying prints is proper lighting...makes a huge difference.

+1
often forgotten

[shadowblade]

Certainly the much greater dynamic range available from a transmissive display device offers a different viewing experience than a print.

I was looking at a collection of still images on a 60-inch, 4K ultra-high-definition TV in a big-box store recently and I must say the monitor technology is getting pretty good at the high end.  Still, some things I'd like to see in a dedicated transmissive display device for photography:

• More resolution.  I don't know what the appropriate metric is: 128 px/inch? 256? ... 1440?  But the 60-inch TV in the store didn't have enough pixels.  Maybe an 8K monitor of that size would be sufficient, but even there I have my doubts.
• Square form-factor to accommodate both horizontal and vertical formats.
• Wide gamut.  I think this is important.  Maybe it's just that most sRGB devices are used without color calibration.  The colors in photos displayed on my wife's iMac monitor look pretty good after I calibrate it, as long as I don't compare them with the same images on my wide-gamut NECs.  (The samples in the store mostly looked over-saturated to me, but I suspect they were processed that way intentionally.)
• Color stability.  Apropos of calibration, if I hang a large monitor on a wall it really would be nice if it could retain its colors for at least six months and preferably a year between calibrations.  Again, I'm not certain this is a requirement since I wouldn't be using the wall-mounted monitor for soft-proofing; maybe the color slew wouldn't be objectionable as long as the monitor was used just for display purposes.

I'm inclined to add a fifth point, which is that such a device should be affordable.  But that's more of a wish than a requirement.

I think we can do better than that.

Monitors are great for doing lots of different things - as luminescent devices, they have a far higher contrast ratio than current prints, and, unlike a print, what they display is interchangeable many times per second. But they're expensive, require a data source and processor to tell them what to display, have less resolution than a print and are only manufactured in so many sizes and aspect ratios. For many images, that means letterboxing, as well as a great big monitor frame around them to ruin the effect.

For static images, an even better solution would be a flat, evenly-illuminated panel. A bit like a light-box used to view X-rays, but a much more sophisticated example of materials science and engineering than a fluorescent tube behind a translucent plastic sheet. Preferably a material that can be cut to the size and shape of whatever it is you want to display - whether you want a square format, a 3:1 panorama or a circle, you can get it, and with no letterboxing. With a light source on one side of the material, the other side is evenly lit - perfect for permanently or temporarily mounting a translucent, backlit print. Most likely it would take the form of a sheet of tiny LEDs on one side (probably consisting of circuitry printed onto fabric or polymer sheet, cut to size/shape), a translucent diffusive material in the middle to turn the forest of LEDs into an evenly-lit front side, and the backlit image mounted onto the front of it (or even printed directly onto the front of the diffusive material). Attach it to a power source, then you can hang it directly on a wall, put it in a frame, facemount it to glass/acrylic or even wrap it around a pillar or a corner of a building. You could potentially even print the LED circuitry directly on the back of the diffusive panel, but keeping the panel and the LEDs separate would make them easier to replace when/if some of them fail. All these materials exist - the optical materials, the sheets of LED material, etc. They just need to be put together, and made cheaper for mass production.

[N80]

Or what about a uniform, perfectly white light source like you mentioned with a color positive film over it? Of course that is the definition of a slide on a light box but I'm thinking of the slide as a printed color negative on translucent clear 'paper' that could be placed over this perfectly flat, perfectly lit, perfectly white 'light box' that can come in any shape. Just thinking inside and outside the box. Not sure what type of print quality could be obtained on transparent film.

[Peter McLennan]

For "normal" viewers and "normal" viewing distances (ie, other than nose-in-print photographers) a large monitor image would probably be indistinguishable from a print of the same size.

I have a 58" Samsung playing a "best of" slide show in one room of my house.  It generates more oohs and ahhs from visitors than any of the 60" prints in the other rooms.  The images please me, too.  And that might be the most severe test of all.

Screen-filling 16X9 images look great, verticals not so much. The biggest disadvantage I see is the problem with verticals.  Even on a 58" 2K monitor, they pretty much suck. 

I need two monitors.  One for each aspect.   

[Farmer]

An inkjet printer has a max resolution of 2880 dots per inch. The resilution of the digital file needed is then 730 pixels per inch.
How to relateren this with displays? Is the dots per inch the measure or the pixels per inch?

TL;DR - compare PPI.

Epson Large Format printers have a max output resolution of 2880x1440dpi, but some consumer models can do 5760.  In either case, max input resolution is 720ppi.  Digital displays are ppi, so it's the second figure that we need to compare (the inkjet uses multiple dots to achieve each pixel).  A 65" TV, for example, is 56.7" wide.  To achieve 720ppi, it would need a resolution horizontally of 40,824 pixels.  In a 16:9 arrangement, it would need 22,964 pixels vertically, for an effective MP of about 937.5MP.

Of course, to get 720ppi input for a printer to make a 56.7" wide print would also require such an enormous input MP.  However, the printer can quite easily produce such a large print from 360ppi input, which would need 234.4MP which is a bit more realistic with stitching, for example.  You can even go to 180ppi and still get great results that still stand up to close inspection (much closer than either the print or TV should really be viewed) and you'd only need 58.6MP.

So that sounds like the display is much better, right?  You only need 8ish MP to do it on the TV at 4k.  The difference is that the printer still has that 2880x1440dpi for putting dots of ink on the page.  Until you use a loupe, it appears to be solid colour and coverage over the print whereas the TV has a definite grid pattern (albeit at a point where you really shouldn't be that close to view it).

In short, they're very different, but you can get excellent results in very large prints and have them in multiple locations for a fraction of the cost of having multiple 4k displays and you can choose a variety of substrates, frames (or not), etc.  In our office, we have some huge prints done on fabric - just like you'd print directly onto a t-shirt, but 2.5m high and 2m wide on a frame.  They look amazing and the impact is far more than the images from projectors on the wall.  You can have any orientation or dimensions you want with a print without "wasting" pixels, too - you're not confined to 16:9.