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Expected Quality?
#1
I'm not sure about the quality we can expect from a resin printer with an external screen.

Asking the company you get always the same answer "It only depends on your phone screen quality - higher resolutions will result in better prints" or the like.
I don't think so. I'm a media designer, and I have some practical experience with hardcopy with contact film and it's issues (film/photo paper, film/nyloprint, film/printing plate, the standard before the digital revolution in printing industry).

I tried a quick demonstration what I expect to happen, see below what I'm talking about:

[Image: i43411bej4yq.jpg]

We can expect that it works. Definitely.
But I think, even if the screen resolution increases, we can't expect sharp edges, small details or any good reproducibility across phones. Quality depends purely on the gap between physical mask (screen) and the photosensitive layer (resin).
In print industry the issue is known as "dot gain", or "bleeding" in image processing. Even the position of the emulsion side of the film had a significant effect.

I worked with nyloprint years (decades?) ago, and there it is clearly visible that the gain/bleeding increases drastically with the distance. This is a physical issue.
Have a look at the this nyloprint ornament, how it increases with nearly 45 degree slopes and gets round corners at its base:
Quote:http://www.belgravur-bvm.de/produkte_lackplatten.html
[Image: produkte_lackplatte.jpg]




I think this is why ONO preferably chooses these "wobbly" structures for demonstration:
[Image: c06bb6b2aa260b8cd895fa27d5905096_origina...2b89f9c247]
(this and following images taken from their kickstarter campaign)

Looking at the end of their kickstarter page, I'm pretty sure this one can never be achieved with the technique:
[Image: 0dc6a56ed8888fe951f3ce3a2874d461_origina...eedb23c8ba]

Looking at these sharp rifles and edges, this one might have been a "real" laser SLA print "just for illustration", too ('tho I hope it wasn't)
[Image: 546df1d6ac88dbadd9975db740472f88_origina...88ef9ca78f]

So the main questions for quality will not be the phone resolution, but:
How large is the ONO gap, will there be future projects with even smaller distance? What is the phone with the thinnest glass and without raising border available? What will be the smallest and sharpest detail we can print? I'm curious for results (some day).
#2
I thought they made a clame in their promo that the better the phone resolution, the better quality print.  It must have some kind of factor.
#3
(06-21-2017, 07:19 PM)Lord.Lethris Wrote: I thought they made a clame in their promo that the better the phone resolution, the better quality print.  It must have some kind of factor.

Yes they did anywhere, but they are probably wrong. As long as the gap (glas+film+???) is larger than a pixel or two, a better resolution will not rise the quality any more. That's what I wanted to show here: blurred is blurred, no matter the underlying resolution, sharp details will get lost. Without focused projection, this is a physical law ono can't beat with anything else.

Of course we have to wait and see how significant the effect will be in daily use, and if such a printer will be useful for sharp scale model parts i.e., or just for dust catchers on a cupboard.
#4
the film between the phone and the resin is pretty thin.
#5
@joeydee remember though, that the quality should stay the same throughout the print as the layer being printed is always in the same place  - i.e. same distance from what is effectively the "print head" (screen).

Your nyloprint quality example is because of the increasing distance between the print head and the object as it gets taller. This shouldn't happen in the ONO's case, or any SLA printer really.

Of course there is the issue of what is actually imaged to begin with and how much the physical attributes of the film and density of the resin interfere with the clarity of the image.

(Unless I'm completely mistaken in which case I shall beg for forgiveness for my insolence :-)
(This post was last modified: 06-29-2017, 10:20 AM by bigRed. Edit Reason: spelling, punctuation & other shit )
#6
I didn't say the quality changes with height. I'm always talking of the resin layer being exposed, the one closest to the screen.
The nyloprint just shows, how much any gap affects the print quality significantly and is smoothing out any details. When the gap is constant, the smoothing is constant. But no smoothing is impossible: even without film (0mm), the phone glass keeps some distance to the LED layer (glass, touch layers, adhesives, ...).

An example (really just a fictive example, try your own figures) :
Let's say we have a pixel density of 200px/mm on a given phone.
Being 0.2mm away from the pixels' light, this will smooth out a radius of about 0.1mm assuming a steep scattering angle, maybe a little more, maybe less. This 0.1mm still contains 20 pixels in diameter, this means any detail below 20 pixels will get lost or at least clumsy.
With a doubled phone resolution of 400px/mm, there are indeed more pixels in the same radius, but with the same gap, the physical smoothing radius remains the same in mm. Just 40 pixels in diameter get smeared to the same clumsy detail.

My statement: There will be a physical limit in detail with those printers, no matter the resolution.

Any guesses how far away we are (air/glas surface to LED layer) with actual phones? The LED layer is the bottommost one. It seems to me it is much more than the 0.2mm of my example. Guessing at least 0.5-0.8 on a galaxy S5.

You can guess the distance by looking from directly above on a sharp line on your display, then marking this line with a sticker, and finally looking at an angle of 45 degrees "under" the sticker (parallax effect).
#7
Hmm - wigs. I see your point.
#8
lol.  every day is a spam purging day with MyBB.!
#9
Oh I thought it was a real comment - confusing but real...
#10
lol

Ooo, talking of spam, some more has appeared over in another thread...

**runs off to deal with spam**


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