iMac 24" backlight bleed/IPS glow

[coffeym]

I got a 24" iMac last summer. Out of the box I noticed what I felt was significant IPS glow, but more-or-less pacified myself that this was normal. As time has gone on, it hasn't got worse, but it annoys me more and more. For reference, my office is generally quite dark, and certainly dimly lit in the evening, which is my preference.

So...is the attached picture normal or ridiculous? It's taken with all lights off, and brightness set at around 25-30%, showing what should be a pure black screen. Compared to the Studio Display, well...there's no comparison. It's really bad.

Not much I can do now, but just interested in your thoughts.

 

[Puonti]

I think you're referring to backlight bleed - the light emanating from the corners of the display in the photo?

IPS glow refers to the fact that IPS LCD panels can't produce a pure black, so what you see instead in a dark room is a grey color. The "+" shape in the middle of the display in your photo is IPS glow (it's present in the corners, too, but overpowered by backlight bleed). IPS glow comes with the territory, so if it bothers you you'll want to look for other display tech, like OLED (of course, there's no iMac with OLED).

Backlight bleed on the other hand is caused by minute frame imperfections at the edges of the display, where the backlight / edge-light finds a way to leak to the front of the display. While it's possible to come across a unit that shows very little of it, it's quite common unfortunately and can develop over time as well. Sometimes it's accepted as grounds for a return (if it's really obnoxious), but it really depends on the vendor. I've had one iPad Pro exchanged due to extreme backlight bleed, and my current one has developed some over the years (but I live with it).

Your photo shows pretty uniform backlight bleed, which I'd say is the best kind you can have if you're going to have it. I can't really say if it's extreme or not, as a photograph can exaggerate the brightness.

 

[Iliketheapples]

Probably should just turn the room lights on instead of living in a bat cave. Probably won't notice it then.

 

[AVE№TURA]

So you couldn’t be further from the truth about OPs post the photo above definitely shows IPS glow as it’s coming from the corners because they are the furthest away from the viewing point and also, because these are not viewed from a 90° angle straight on like the portions of the display that are closer to the centre.

Backlight bleed or even uniformity looks different, not a symmetrical is this

And yes I was also sad to find out that the iMac 24 doesn’t have the same optical layer stack in between the LCD in the front glass like it is the case on the studio display. In fact I’m really disappointed.

 

[videojanitor]

I noticed the same thing when I bought an M4 iMac a couple of months ago. It was a bit shocking to see this, as the previous iMac (2017, 21.5” Retina) did not exhibit this problem. It hasn’t proven to be a real issue in day-to-day use, but with dark content it’s visible, especially if not looking at it dead-on. I’d be curious to learn the technology difference between this panel and the 21.5”.

 

[AVE№TURA]

I noticed the same thing when I bought an M4 iMac a couple of months ago. It was a bit shocking to see this, as the previous iMac (2017, 21.5” Retina) did not exhibit this problem. It hasn’t proven to be a real issue in day-to-day use, but with dark content it’s visible, especially if not looking at it dead-on. I’d be curious to learn the technology difference between this panel and the 21.5”.

The tech behind the 27 and 21.5 inch imac is probably some sort pf ATW pollarizer or a similar effekt by adding some optical stack like a filter.
Apple quality was better 2010 to 2019.

Apole products were special because of quircks like that! There were no better displays in other systems but now macs are mainstream