Weird colours on iMac screen

Gullly · 05-11-2009, 04:09 PM

This could be a screen problem so sorry if it's in the wrong place.

Ok, first my computer - 20" G5 iMac, 2.16 GHz Intel, 1 GB RAM, ATI Radeon X1600 and Mac OS X 10.4.11 EMC:2118

I was talking to a friend on web cam the other day when after an hour or two the screen suddenly went tinted green all over. You could still see everything but it was all green and some of the edges of windows and other things had gone all jpeg-ish (as in areas looked like an image compressed in a lossy format but more extreme). Then the screen turned completely green (3 shades of green in vertical stripes each abut 2-3 mm thick), so nothing else could be seen. At this point I could still talk to my friend through the microphone - just see nothing!

I turned it off and on again and it was fine for a little while, then a new problem occurred. Suddenly a weird magenta colour had appeared in the dark sections of the screen. This is the problem that remains. Sometimes it changes a bit and at the moment it seams to have stuck with a greenish yellow as well as the magenta for a while, but there has also been an intense white, in a similar style to the magenta and green. These colours are solid and vibrant and are not still - they seam to glisten/twinkle as different pixels light up. Sometimes there's also a red/orange and yellow tint to areas. The red/orange colour more often comes in lines though (not strait lines - following the lines of an image for example highlighting the lines on a face or in hair)

Here's an image as it should be and a photograph taken of the same image viewed through my screen, showing the magenta and green problem clearly. What you can't see is the movement of the pixels

Text seems to be pretty much unaffected, even black text, which is odd considering it seems to target the dark areas of images.On this page the only thing affected is the 'Tech Support Forums' Logo. The smilies are fine, as is the advert at the bottom.

I've tried turning it on and leaving it overnight but the problem persists. I don't think the distortion is copied through a print screen but it's hard to say because I can only view it on this computer with this screen, so if it didn't copy the distortion, then it would just be reapplied by my computer anyway.

Ok, I've tried to give as much detail as possible... maybe too much! tell me if I've missed anything. I think it must be a video card problem but if anyone thinks there's something wrong with my screen - please let me know. Any help much appreciated.

Gullly · 05-11-2009, 04:37 PM

I also posted this in the video card section and someone told me to try it here. They advised that I reinstall my drivers (if a Mac has drivers) but I'm not sure how to do that on a Mac (if possible)

More recently a strange rippling yellow has replaced the white areas on my screen but disappeared on reboot.

05-11-2009, 04:09 PM	#1 (permalink)
Gullly Registered User Join Date: May 2009 Location: Greenwich, London, UK Posts: 8 OS: Mac OSX 10.4.11	Weird colours on iMac screen This could be a screen problem so sorry if it's in the wrong place. Ok, first my computer - 20" G5 iMac, 2.16 GHz Intel, 1 GB RAM, ATI Radeon X1600 and Mac OS X 10.4.11 EMC:2118 I was talking to a friend on web cam the other day when after an hour or two the screen suddenly went tinted green all over. You could still see everything but it was all green and some of the edges of windows and other things had gone all jpeg-ish (as in areas looked like an image compressed in a lossy format but more extreme). Then the screen turned completely green (3 shades of green in vertical stripes each abut 2-3 mm thick), so nothing else could be seen. At this point I could still talk to my friend through the microphone - just see nothing! I turned it off and on again and it was fine for a little while, then a new problem occurred. Suddenly a weird magenta colour had appeared in the dark sections of the screen. This is the problem that remains. Sometimes it changes a bit and at the moment it seams to have stuck with a greenish yellow as well as the magenta for a while, but there has also been an intense white, in a similar style to the magenta and green. These colours are solid and vibrant and are not still - they seam to glisten/twinkle as different pixels light up. Sometimes there's also a red/orange and yellow tint to areas. The red/orange colour more often comes in lines though (not strait lines - following the lines of an image for example highlighting the lines on a face or in hair) Here's an image as it should be and a photograph taken of the same image viewed through my screen, showing the magenta and green problem clearly. What you can't see is the movement of the pixels Text seems to be pretty much unaffected, even black text, which is odd considering it seems to target the dark areas of images.On this page the only thing affected is the 'Tech Support Forums' Logo. The smilies are fine, as is the advert at the bottom. I've tried turning it on and leaving it overnight but the problem persists. I don't think the distortion is copied through a print screen but it's hard to say because I can only view it on this computer with this screen, so if it didn't copy the distortion, then it would just be reapplied by my computer anyway. Ok, I've tried to give as much detail as possible... maybe too much! tell me if I've missed anything. I think it must be a video card problem but if anyone thinks there's something wrong with my screen - please let me know. Any help much appreciated.

05-11-2009, 04:37 PM	#2 (permalink)
Gullly Registered User Join Date: May 2009 Location: Greenwich, London, UK Posts: 8 OS: Mac OSX 10.4.11	Re: Weird colours on iMac screen I also posted this in the video card section and someone told me to try it here. They advised that I reinstall my drivers (if a Mac has drivers) but I'm not sure how to do that on a Mac (if possible) More recently a strange rippling yellow has replaced the white areas on my screen but disappeared on reboot.