In article <YJ********************@reader1.news.saunalahti.fi >,
"Jukka K. Korpela" <jk******@cs.tut.fiwrote:
Scripsit Felix Miata:
On 2007/05/21 09:48 (GMT-0700) Kevin Scholl apparently typed:
For the record, that is #666 on a background that is #EEE fading to
#FFF (white). Studies for years have shown that high contrast such a
black on white cause the eyes to tire quickly, so I softened the
contrast.
Sounds like urban legend to me.
I don't think it even counts as an urban legend. It's simply crap, nonsense,
or trolling.
Well, I can't speak for actual studies, but my uncle is a specialist in
lighting and vision (reader in ergonomics at Loughborough University,
now retired[1]) and we've had this conversation...
High contrast environments are generally harder on the eyes,
particularly black text on a white or clear background at high light
intensity levels (e.g. a printed page in strong sunlight, staring at the
screen for a really bright overhead projector, etc.) [0] BUT...
Whether or not this situation has a noticeable effect on the person
looking at the high contrast depends on a number of factors, including
duration, age, eye health, and ambient light levels. In other words,
there's a difference between staring at a projector screen in a room
that is otherwise completely dark, compared to the same screen in a
room with normal ambient illumination (e.g. window shades open)
Where this becomes really important (and my uncle's particular interest)
is for people with eye problems such as cataracts; you can actually
improve their ability to read a book by reducing page contrast (use an
incandescent light on a dimmer, or a shade that colours the light.)
I don't know how this translates to the specific situation of monitor
screens[2], since at the time I asked about this computers where not in
widespread use, most monitors used white or green text on a black
background, and video data projectors were an expensive novelty.
That's a whole other field of research and, from what I've seen reported
in the media, seems more to do with focus-related eye strain. This would
get back more to using a font SIZE that was reasonably legible at a
comfortable viewing distance from the monitor (and only the individual
user really knows what that is for them!)
There are, in addition, certain background/foreground colour combinations
which can result in fuzzier-looking text on lower dpi monitors, due to
the use of separate RGB pixels. I suspect (although I don't know) that
this is not as much of a problem with modern screens that have the three
colours in different layers and higher intrinsic physical dpi.
Of course, that still doesn't excuse things like pale yellow text on a
white background or, in the case of one site I visited (once!), dark red
text on a forest green background...
[0] There's a reason (quite apart from premature burn-out/burn-in) that
early monochrome CRT displays used a black background.[3]
[1] He was one of the first to study the effects of fluorescent lighting
on employees in offices.
[2] I'm quite sure ergonomists have studied the effects of screen
contrast and intensity vs. duration of use, but I'm equally sure
I can't be bothered to look it up. Besides, a computer user can
adjust brightness, contrast, and ambient light levels to suit.
[3] You know you've done too much C programming when your footnotes
are zero-indexed...
