[maemo-users] writing HTML for tablets

From: Mark wolfmane at gmail.com
Date: Sat Apr 12 23:30:15 EEST 2008
On Sat, Apr 12, 2008 at 11:55 AM, Olivier Ricou <maemo1 at altribe.org> wrote:
>  Think that 300dpi
>  printers have been replaced by 600dpi ones when most screen are
>  less than 100dpi.

You don't understand how printers work. The *dot pitch*, (that is, the
distance from the edge of one dot to the *same* edge of the next dot)
may allow for 600dpi or even much more, but the actual dot *size* is
unrelated to the pitch, and is actually much larger. The actual dots
overlap, so while the *pitch* may be higher, the dots are larger as
well. In other words, a "600dpi" printer's dot *size*, and therefore
"true" resolution, is much lower than the numbers imply.

That's why laser printer resolutions are so much lower than ink jet
printers: the nature of the mechanics makes for much less overlap with
laser printers, and therefore lower dot pitch.

Printiers are completely different from computer monitors (which have
zero overlap of pixels), for which the dot pitch and the pixel size
are directly related.

If you look at a photo in a magazine or newspaper through a magnifying
glass, you will be amazed at how large the dots actually are. The
human eye is capable of amazing resolution, but the human brain is
capable of even more amazing processing, and you see what your brain
thinks you *should* be seeing rather than what you are actually
seeing. That's why mosaics work, and why once you've been watching an
analog TV image for a few minutes you don't notice the graininess
caused by the relatively large pixels (provided the signal is strong
and there's no "snow" or other obvious interference). You only notice
the low resolution if you're thinking about it and looking for it.

To sum up: your brain is capable of more or less increasing the
resolution of low-res, but relatively large, images, but can't make up
for details that are simply smaller than the optics or physical
resolution of your eye can handle.

>  I have a 1600x1200 15" screen and before I had
>  a 1400x1050 for the same size. I do appreciate the difference
>  and since my computer is quite old, I look for higher resolution.

Actually, I have the same issues with the N800's screen. I have -9.5
diopter lenses, and if I take out my contacts or remove my glasses and
hold the N800 about 6cm from my eyes, I can clearly see the individual
pixels. However, with my contacts in and using 1.75 diopter reading
glasses, the dot pitch of the Nokia's screen is still very much at the
maximum end of usability. Increasing the resolution at that screen
size would be very much counterproductive.

>  The only limit I can see is the size of the text in mm (or inches)
>  which is quite different since you always can increase the size
>  of the font if your resolution increase.

This also has usability issues, since different apps handle "zooming"
differently, and often create other usability problems when font sizes
are changed or zooming is enabled.


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