
Designer's guide to DPI - alfredxing
http://sebastien-gabriel.com/designers-guide-to-dpi/
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swerner
I was expecting an article about DPI (as in raster printing dots), but it
ended up being about PPI (as in screen pixels).

DPI in print is something I see many get wrong, and most don't understand the
difference between DPI, LPI and PPI.

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pawadu
I find it hilarious that on a page about cross-platform design the left menu
hides part of the article text on the ohh-so-common 1920x1080 displays.

I guess to some people cross-platform means "works on my imac 5K _and_ my MBP
retina"...

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ovao
> This statement is true for the range of devices' screen size it's used in,
> but as the screens are getting better and better, our eyes are now trained
> enough to perceive the pixels - especially for rounded UI elements.

I'm not quite sure where this thinking has come in. The "Retina" moniker
applies to displays based on the resolution, the size of the display and
typical viewing distances for devices of that size and type. What science has
suggested that our visual systems get better at resolving detail as display
densities increase?

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bfred_it
Think of when you used a retina display for a while and then looked at a non-
retina one:

"ew, why is this disgusting now?"

I think that's what he's trying to say: not that our vision physically
improved, but that we started to notice the roughness of lower-res displays.

Imagine a future where all displays are "Retina" at 1-inch distance; you'll be
annoyed that when looking at a lower-res display it won't show someone's nose
hair.

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anmorgan
I know it's picky and this article is trying to be simplistic, but pixels do
have a physical size. That is why there are optimal resolutions, starting with
a 1:1 representation of physical to software.

Edit: Actually the first paragraph of "Resolution, pixel and physical size"
kind of really causes confusion, since he is trying to redefine standard
definitions, and then tries to provide reasoning for the redefinition. This is
mainly a note of caution.

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Gracana
Where / in what way is it implied that pixels don't have size? What is
"redefined"? I think the article explained the concepts very well.

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anmorgan
From the article:

"Asking someone what the size of a pixel is is a good way to confuse him or
her because it’s a trick question. A pixel has no size, no physical value or
meaning outside of its mathematical representation. It is a part of a
relationship between the physical screen size, expressed in inches, the screen
resolution, expressed in pixel per inches and the pixel screen size, expressed
in pixels. Laying it all out, it looks like this:"

"As you might have noticed in my explanations, “Resolution” stands for PPI, in
this case “109” but not “2560x1440”, like you might commonly see everywhere on
the web."

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enra
There is no date on this post, but few details point this to be bit outdated.

Lot of mobile assets are now svg (Android), pdf (iOS) or programmatically
created. Most of the time if you design in Sketch, you don't really need to
worry about the pixels since all the assets are in vectors. You can just spec
everything in pt and export the assets in svg or in the desired 2,3x,
whatver-x as needed.

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rovr138
[https://hn.algolia.com/?query=designers%20guide%20to%20dpi&s...](https://hn.algolia.com/?query=designers%20guide%20to%20dpi&sort=byPopularity&prefix&page=0&dateRange=all&type=story)

Seems the oldest submission is at least 3 years old.

