

Show HN: Can you see a single pixel on a retina display? - 1as
http://oneretinapixel.com/

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leot
Oh for heaven's sake,

[locate individual high contrast pixel] != [ability to distinguish individual
pixels]

Vision and visual acuity is not this simple. See, e.g.,
<http://www.michaelbach.de/ot/lum_hyperacuity/>

I don't actually know, but perhaps seeing something as pixelated requires
being able to resolve the edges of an individual pixel.

A better test would be to see if people can detect a difference in the pixel
"phase" (for lack of a better word) of some pixel-drawn object (that is, show
identically shaped objects that have a different internal pixel organizations
because of their position on the screen). Do an ABX-style test, see if you can
tell the difference.

I'll bet you can tell the difference on a classic display. I'll bet you can't
on the iPhone 4+.

[edit: made the comment slightly nicer ... :/]

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frou_dh
> Oh for heaven's sake ... Vision and visual acuity is not this simple.

You just gave me flashbacks to the old chestnut of humans allegedly seeing a
fixed "fps", and it conveniently topping out at the same nice round number
that the nearest TV and/or theatre can produce. I bet that's still being
propagated daily on forums.

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nell
This is not the right test. Retina doesn't mean a single pixel would
disappear.

I think the real test would be to draw a curve of one pixel thickness and be
able to see a smooth curve and not a pixelated one.

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1as
I love my retina displays, but Apple's marketing annoys me as I can still see
pixellation at times. This is a quick game to see if you can dispute the
marketing claim.

Looking forward to a real retina display soon :-)

~~~
foolrush
I am unsure what "real retina" means.

A typical print project will expect images at 300 PPI. Text however, is
provided in spline. This is typically rendered at 1200 PPI by the rasterizer.

In terms of printed quality display, it would likely mean several more
generations of display technology before we see the equivalent density.

~~~
1as
I quoted Apple's Retina claim on the site: ‘The Retina display’s pixel density
is so high, your eye is unable to distinguish individual pixels’. (They have
many variations on this).

So for me a real retina display would make a single white pixel on black
background invisible at normal viewing distances to a normal eye.

~~~
ISL
By that logic, because the diffraction limit of the human eye is orders of
magnitude away from being able to image a star, we cannot see stars.

For resolution, the question might be better stated: Can you tell the
difference between

    
    
       a)        **
    

and

    
    
       b)        * *
    

The two images have the same aggregate intensity, but different morphology.

The ancients played the same game as a vision test with stars:

<http://en.wikipedia.org/wiki/Mizar_and_Alcor>

~~~
1as
Very interesting – thanks.

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bsimpson
This is why @2x is silly. The only way to stay ahead of the constant march of
technology is with vector graphics. Otherwise, your @2x image is going to look
silly on an @3x display (or zoomed in).

~~~
xnxn
I love SVG but it's not a solution in all cases, e.g. for photographs. Raster
graphics are very much here to stay.

~~~
bsimpson
Very true, but most @2x PNGs are just vector icons that have been rasterized
because people don't realize SVG support has landed in modern browsers.

Photos are a whole other ballgame.

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LowKarmaAccount
The "Retina" display is just a marketing term which means that a person with
20/20 vision cannot distinguish individual pixels _at a certain distance_.
Movie screens do not need to have a high ppi ratio because you view the screen
from a greater distance. If you have better than 20/20 vision, or press your
face up against the screen, you will be able to resolve individual pixels
quite easily.

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jerf
While I appreciate that you're specifically referencing Retina claims and
therefore you really do need a "Retina" display for it to matter, I'd suggest
against actively locking out everybody else. It's generally an interesting
question about a given display and one's personal eyesight even without the
hook of testing a marketing claim.

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filvdg
with the bad pixels in my display i had to find the "artificial" one lighting
up

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glazskunrukitis
Uncaught TypeError: Cannot read property 'parentNode' of null (JS console)

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1as
Thanks – this should be fixed now.

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yoster
I'm getting fucking old. Everything looks slightly blurry.

