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Old 05-08-2011, 10:23 AM   #1
cantab
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Monitor colour reproduction, brightness, gamma woes


I can't get my main monitor, a rather old CRT, to reproduce colours properly. I'm using the proprietary nVidia driver, and have tried stuff with its brightness and gamma settings, but I always either get deep greys indistinguishable from black, or light colours look washed out.

Anyone know what settings I could try changing, in what order I should do things, etc?

(My secondary monitor, an LCD one, for whatever reason is unaffected by the setting changes - so by displaying the same image on both I figure I can try and make them look the same - but what's a good test image?)

Last edited by cantab; 05-08-2011 at 10:24 AM.
 
Old 05-09-2011, 05:16 AM   #2
rylan76
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Originally Posted by cantab View Post
I can't get my main monitor, a rather old CRT, to reproduce colours properly. I'm using the proprietary nVidia driver, and have tried stuff with its brightness and gamma settings, but I always either get deep greys indistinguishable from black, or light colours look washed out.
AFAIK old CRTs will start doing this. If I remember right it has to do with the field coils and the electronics driving them deteriorating over time. Also, if you have some "burn in" on the phosphors on the front of the inside of the vacuum tube, this might contribute to ghosting or having washed-out colors. I had this on an old Phillips 1917 color CRT I used to use. There is no settings or things you can change to fix this type of problem usually, you need a new display.

I seem to remember as well that some CRTs could be calibrated as regards their electron guns at the back (or had to be calibrated) - maybe yours has gone out due to age??

Did the screen receive any bumps or knocks recently?

Why not just replace it with a modern flat-panel display??

Last edited by rylan76; 05-09-2011 at 05:17 AM.
 
Old 05-09-2011, 05:19 AM   #3
Soadyheid
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Quote:
so by displaying the same image on both I figure I can try and make them look the same - but what's a good test image
The technologies are totaly different. CRT displays age and the phosphors making up the display degrade causing the tube to "go soft" causing brightness/contrast problems and fuzziness. You also have colour purity adjustments which involve moving scan coils and magnets attached to the neck of the tube. Then there's RGB convergence which will depand on whether you've got in-line or delta configured electron guns... (Later tubes were in-line and easier to set up!) Yup! a nightmare. I've spent quite a few years setting up CRT displays and the image displayed is always subjective when comparing it with another. What's Ok for one person isn't for soneone else. You'll never get a true match, best efforts only.

Displays are usually set up using diferent images; all red, green or blue for the colour purity set up plus white grids to set up convergence.
Note LCD displays don't need convergence set up as you have no electron guns to align.

My

Play Bonny!
 
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Old 05-09-2011, 05:37 AM   #4
cantab
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Why not just replace it with a modern flat-panel display??
Money.

Well, I had wondered if it was a case of it aging. If it's not going to be possible to get a "perfect" image, then at least I now know it'll be a waste of time trying.
 
Old 05-09-2011, 09:07 AM   #5
rylan76
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Money.

Well, I had wondered if it was a case of it aging. If it's not going to be possible to get a "perfect" image, then at least I now know it'll be a waste of time trying.
I agree with the above poster - you're just wasting time. Once a CRT has started doing this, it can only be "repaired" by buying a new CRT...

I understand the $$$ angle, but a good, standard (nothing fancy) flat-panel LCD display cannot be THAT expensive surely? I bought my 17 inch LG Flatron L1919S about two years ago for about $215 US... this being here of course (South Africa), with all the import costs, etc. etc. I bet if you're in the UK you can get something a lot better and bigger for a lot cheaper than that.

Last edited by rylan76; 05-09-2011 at 09:09 AM.
 
  


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