New 27-inch iMac screen query

thomas223

macrumors member
Original poster
Nov 29, 2011
51
1
Hi,

I purchased a new 27-inch iMac about a week and a half ago but returned it after I noticed 3 annoying things on the display:

1. Very fine horizontal lines on the screen when it displays only black. These lines run all the way across the screen from left to right. The easiest way to see these lines is to view the screen in a very dark room with your face very close to the screen.

2. I noticed an off-white horizontal line at the bottom of the screen when it displays only white.

3. The final thing I noticed were uneven lighter areas in the corners when the screen displays only black. I don't think it's a light leak because when I move my head directly in line with a corner, the abnormality disappears.

I exchanged it for another iMac but the new one does the exact same thing so I'm not sure if all iMacs have these characteristics or whether I received two faulty units from a larger defective batch.

I've attached a few images of the issues. If someone could have a look at it and let me know if this is normal or not, I would appreciate it. I spent a lot of money on this iMac and I don't want to have issues a few months from now.

Thanks
Thomas
 

Attachments

Last edited:

thomas223

macrumors member
Original poster
Nov 29, 2011
51
1
I placed a red block around the darker line on the white screen but it didn't come out very well. Please look at the area below the red line on the white screen.
 

leman

macrumors G4
Oct 14, 2008
10,766
5,262
Yeah, my iMac has similar effect. I guess its what they call IPS glow - as it only appears when you are viewing the area from a certain angle. Because the screen is so big, you wil always have that certain angle in the corner. Its definitely the panel, as the Dell monitor based on the same panel also exhibits the glow.

But let's be honest, even with the glow, the iMac display is still tons better than most others in the market...
 

thomas223

macrumors member
Original poster
Nov 29, 2011
51
1
Thanks for the reply. At least now I know that one of the three issues is normal for this type of screen. Do you also experience the other two issues?
 

Lankyman

macrumors 68020
May 14, 2011
2,011
763
U.K.
I suspect you're the kind of guy who spends most of his time finding fault with the PQ of HD programs rather than enjoying the content.


The easiest way to see these lines is to view the screen in a very dark room with your face very close to the screen.
I think the above says it all really. :eek:
 

leman

macrumors G4
Oct 14, 2008
10,766
5,262
Thanks for the reply. At least now I know that one of the three issues is normal for this type of screen. Do you also experience the other two issues?
I also see (or believe to see) the thin white lines you speak about when the display shows black. That said, they are really unnoticeable if you are not pressing your nose into the monitor :)

I don't see a distinguishable bar on a white background though... there may be some slight uneven lighting "smudges", but nothing like what your image show.

I am not photographer though, so I am not trained in such things :) Needless to say, I am very happy with my iMac display :)
 

thomas223

macrumors member
Original poster
Nov 29, 2011
51
1
I suspect you're the kind of guy who spends most of his time finding fault with the PQ of HD programs rather than enjoying the content.




I think the above says it all really. :eek:
I can see the horizontal lines when seated at my desk, working on the iMac. That is why I wrote 'the easiest way to see' as opposed to 'the only way to see'.

----------

I also see (or believe to see) the thin white lines you speak about when the display shows black. That said, they are really unnoticeable if you are not pressing your nose into the monitor :)

I don't see a distinguishable bar on a white background though... there may be some slight uneven lighting "smudges", but nothing like what your image show.

I am not photographer though, so I am not trained in such things :) Needless to say, I am very happy with my iMac display :)

Great, thanks.
 

derbothaus

macrumors 601
Jul 17, 2010
4,073
13
That is NOT "IPS Glow".
IPS glow is when viewing from 45º angle and it is purple wash over the blacks.
What OP has is terrible backlight uniformity. Or a really bad photo to go by.
Ack. If it were mine I would take it back. Any self respecting Apple store would replace that.
 

thomas223

macrumors member
Original poster
Nov 29, 2011
51
1
That is NOT "IPS Glow".
IPS glow is when viewing from 45º angle and it is purple wash over the blacks.
What OP has is terrible backlight uniformity. Or a really bad photo to go by.
Ack. If it were mine I would take it back. Any self respecting Apple store would replace that.
Hmmm... Now I'm even more confused...

Thanks for the advice.
 

colonelbutt

macrumors 6502
Nov 14, 2007
314
270
London
if you look at reviews of the iMac you will see that non-uniform back lighting is the only critism of the screen

I am sure that all your effects are normal

It is only a slight issue when the whole screen is black. I use mine for photo editing and its a fantastic screen.
Apparently the iMac is the only commerical monitor that is colour calibrated before it leaves the factory
 

thomas223

macrumors member
Original poster
Nov 29, 2011
51
1
if you look at reviews of the iMac you will see that non-uniform back lighting is the only critism of the screen

I am sure that all your effects are normal

It is only a slight issue when the whole screen is black. I use mine for photo editing and its a fantastic screen.
Apparently the iMac is the only commerical monitor that is colour calibrated before it leaves the factory
that is good to know. thanks!
 

leman

macrumors G4
Oct 14, 2008
10,766
5,262
That is NOT "IPS Glow".
IPS glow is when viewing from 45º angle and it is purple wash over the blacks.
What OP has is terrible backlight uniformity. Or a really bad photo to go by.
Ack. If it were mine I would take it back. Any self respecting Apple store would replace that.
Backlight bleeding won't disappear when viewing the screen from the 0° angle, but this is exactly what happens here. My display shows the glow only when viewed from about 45° angle (as you say) - and this is also what OP describes if I read it right.
 

derbothaus

macrumors 601
Jul 17, 2010
4,073
13
Backlight bleeding won't disappear when viewing the screen from the 0° angle, but this is exactly what happens here. My display shows the glow only when viewed from about 45° angle (as you say) - and this is also what OP describes if I read it right.
Hmm. Maybe Apple is using e-IPS 6-bit on the iMac's? I kind of had similar issue with Dell U2311H. Not an issue with the H-IPS or other 8-bit, 10-bit versions. Almost like corner IPS glow because of the wideness and the 6-bitness. Anyone want a U2311H CCFL version? The AntiGlare coating is obscene.
 

FrankHahn

macrumors 6502a
May 17, 2011
735
2
Hmm. Maybe Apple is using e-IPS 6-bit on the iMac's? I kind of had similar issue with Dell U2311H. Not an issue with the H-IPS or other 8-bit, 10-bit versions. Almost like corner IPS glow because of the wideness and the 6-bitness. Anyone want a U2311H CCFL version? The AntiGlare coating is obscene.
Does this imply that the panels on iMacs are different from those on Cinema or Thunderbolt Displays?

I have two Cinema Displays and I do not have any problems found on iMac panels.

Someone ascertained that the panels on iMacs and standalone displays are identical.
 

derbothaus

macrumors 601
Jul 17, 2010
4,073
13
Does this imply that the panels on iMacs are different from those on Cinema or Thunderbolt Displays?

I have two Cinema Displays and I do not have any problems found on iMac panels.

Someone ascertained that the panels on iMacs and standalone displays are identical.
I'm only implying based on the pics and what I have seen in the past with the e-IPS panels vs. the Eizo, NEC H-IPS variants (Which cost more anyway, e-IPS is a cheaper panel). It's worth looking into as I am definitely not a definitive source. I don;t mind a little change but it is another thing to look square at an IPS display and have glow from all 4 corners.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.