Back in March I wrote about a
I was seeing with my Dell S-IPS LCD monitor.
I got varying reports on the web on whether this was likely to be a
temporary or a permanent problem; so here's an update six months later.
The problem I noticed back in March was that my xchat window, always
positioned at the same spot on the screen, was getting burned into
the monitor. Against a blank white or grey screen, I could clearly
see where that window's titlebar normally was, and rows of horizontal lines
where the text was.
First, I changed my ways to avoid having windows in the same place all
the time. I changed my window manager settings to remove most window
placement settings, I removed directives to show any windows on all
desktops, and a worked on developing a habit of moving windows around
periodically to slightly different locations (I think I'll have my
Firefox window on the upper right this afternoon). I don't really
like that -- I guess I'm enough stuck in my ways that I like knowing
that I can look to the upper left for web pages and the lower right
for IRC -- but it's not that bit a deal.
And, happiness, my burned in xchat lines went away. My old bad
behavior had not permanently burned in the pixels on my nice monitor.
But that's only part of the story -- because if you look at the photo
from March, xchat is not all you see that's burned in. There's also
the wavy stuff going across the lower 1/4 of the screen -- and that
didn't correspond to any window I'd been running.
I thought maybe it was left over from some Windows wallpaper used by
the monitor's previous owner. But none of the standard wallpapers on
my Vaio's WinXP partition have this pattern. (What it reminds me most
is the data I used to analyze from a cell-sorting machine in my first
computer job. Somehow I suspect that's not the culprit.)
These patterns, unfortunately, are not going away. In fact, the ones
along the top and bottom left edges are pretty clearly getting worse,
and eventually, alas, I'll probably have to replace the monitor.
But meanwhile, they vary a lot.
When I first turn on the monitor in the morning, most of the time
I can't see the burn-in at all. After a long day of use, it's usually
pretty obvious. In between, though, there's huge variation. Sometimes
they appear after an hour of use; sometimes I can go most of the day
before the burn-in starts becoming visible.
It doesn't seem to be
particularly temperature sensitive, and it doesn't seem to vary much
with which background image I'm using that day.
Sometimes when I'm going to be away for a while, I display an all
white screen -- I've read a few reports indicating that can help, and
anecdotally I think it does. I should probably keep better statistics on
temperature, background color and time to find out what's really
affecting this. Maybe I could use it as a homework project in the new
Linuxchix R/Stats course!
Update: Two days after I wrote this article, the patterns were
unusually bad starting first thing in the morning, and
stayed bad all day ... then at about 7 in the evening, as I
typed away not doing anything special, over a period of about
15 minutes they disappeared almost entirely. Quite mysterious!
[ 11:47 Sep 23, 2009
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Mostly, I love my
2005FPW S_IPS monitor
. Nice colors, sharp image, incredibly w
ide viewing angles. But one thing made me uneasy:
while working on a smooth gradient in GIMP, I noticed some
funky pixels in the bottom right of the screen, where I could see
horizontal bars where the image clearly didn't have them. And if I
moved the image, the bars stayed put. Oh no! My lovely monitor
maybe wasn't so lovely!
Since then I've been pretending not to notice (I bought the monitor
used, so warranty return isn't an option). But yesterday, I maximized
Firefox on a page with a medium cyan background -- and that barred
area was a lot worse.
In fact, it was so much worse that I could see detail in it: it was
my xchat window. I could even read some of the menubar items.
It's an LCD! They don't get burn-in ... do they?
Well, yes, it turns out, they do. Only it's not called "burn-in",
it's called "image persistence". And for some people,
it happens very quickly, while other people never see it.
Anecdotally S-IPS monitors seem to show image persistence
a lot more easily than TN monitors, but nobody seems to know why.
The good news is that it's temporary -- it's not permanent burn-in
like old CRTs sometimes showed.
The solutions most people suggest:
- turn off the monitor for a time comparable to the time the image
has been burning in
- display a constantly changing screensaver for a long time (hours
- display all white for a long time
On my monitor, about an hour and a half of all-white made it better,
and after turning it off overnight, the next morning I could no longer
see any trace of the persistent image.
Update two days later: Strangely enough, although the pattern
seemed completely gone the next morning, that evening it returned,
even though I hadn't had any window at all in that space all day.
I gave it another hour or two of all-white over that area, then its
usual evening of rest, and the next day it was gone again and stayed
gone this time. At least, it's evening now and it hasn't returned yet.
So I guess I need to change my habits.
I already use power saving mode so the screen sleeps when I'm not
there (no screensaver);
but on the other hand I'm at the machine day and night, and I like
to keep windows in the same place.
- No more windows visible on all desktops
- Try to put windows in different places on each virtual desktop,
and move them around some
- Periodically invert the screen colors
How do you invert the screen? You'd think there would be a gazillion
programs to do that on X, but there aren't. You can compile a C program
sgamma -b -1 to invert, and
sgamma -b 1
to restore. It restores to full brightness, though, so if you've
changed your brightness using a program like
you'll have to adjust it again afterward. Alternately,
Guillermo showed me a nice little C program called
invgamma, by Ben Winslow, that just inverts whatever gamma curve
you already have (run it again to undo the effects). Ben doesn't seem
to have a page for it and it doesn't have any license info in it so I
can't put it on my site either, but if you google for it you'll
probably find a copy.
I'm a trifle bummed that the whizzy S-IPS monitor turned out to be so
delicate. But I suppose it's good to change habits now and then
anyway and not get too stuck on particular window positions.
Maybe it'll help keep my brain from burn-in too.
[ 11:21 Mar 28, 2009
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