Help understanding screen resolution, pixel density and native resolution

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Hey peeps I was wondering if one of you smart people could explain screen resolutions to me? I have recently pre-ordered an "LG 27GN950-B" 4k 144Hz monitor for gaming but I also use my computer a lot for watching tv, movies ect on streaming sites. Most things I would stream or download will only ever be in 1080p quality unfortunately as there is still very limited 4k content or streaming services.

I am upgrading from a 24" 1080p screen to the 27" 4k screen, but is it true that a 1080p image might possibly look worse on the 4k screen than my old 1080p screen due to it not being its native resolution? I would hate to spend lots of money on a 4k screen, just for the majority of things I watch to be 1080p and actually look worse. I am just struggling to wrap my head around why a low quality image would look worse on a better quality screen? Surely if you are looking at a 1080p image on a 4k screen, it would be using a handful (unsure exactly how many) pixels on the 4k screen, where it would only use 1 pixel on a 1080p screen. But as the pixel density is higher anyway at 4k, those handful of pixels being used to show 1 pixel of the image, would look the same as 1 pixel at 1080 anyway.

The only way I can understand an image looking worse on a new screen is if I increased the screen size drastically and it was trying to literally stretch the imagine across 40", thus needing to stretch 1 pixel from the image across dozens of pixels on the screen. But you would have the same problem anyway if you got a bigger screen irregardless of resolution surely even if pixel density stays the same. I am not really increasing the size of my screen as its only getting 3" larger so I cant really understand why it would matter its not the native resolution?

Sorry if this doesn't make much sense, I've kind of confused myself thinking about it. I just cant really understand why it would matter if a screens not at its native resolution if the screen is of higher pixel density and the image is not being stretched any larger. Surely a 1080p film will looks exactly the same on a same sized 1080p and 4k screen?

Also is it reasonable to think I could put the resolution down to 1440p for some games and not notice any difference in quality compared to a 1440p screen showing the same thing if I wanted extra framerate? (Hopefully ((Sometime)) soon getting a 3080 to pair with it). Thanks for your time.
 
Soldato
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I have the same monitor as the one you’ve ordered. I was worried that gaming at 1440p would look worse than on a monitor that runs 1440p natively but it doesn’t it looks just as good at 1440p than it would on a 1440p monitor.
 
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Great to hear nlel1975, to be honest, lowering the resolution would be a last resort, id rather lower graphics settings on the game before i go down a resolution but still curious incase I wanted to try. Im sure even the 3080 will struggle at 4k on upcoming games but I still have plenty of 1-3 year old games that will run 100+ fps at 4k and make the refresh rate worth it also :) Seems like a super adaptable monitor if you dont need HDMI 2.1. Just more curious about media where I am unable to download more than a 1080p file.
 
Soldato
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Sure lower source resolution image is never as accurate as image made for native resolution.
But good scaling doesn't really decrease image quality from original in any meaningfull way.
Also with pixel dimensions being doubled, there's possiblity of "integer scaling":
1 pixel of source is simply showns as 2x2 size on screen.
 
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This is what I am trying to understand I suppose, EsaT. How does image scaling actually work can anyone explain?
The maths of it is a bit confusing to me I suppose. Does a 4k screen have exactly double the pixels of a 1080? If it did surely it would have to take 1 pixel from source and show it was 2x2 pixels on screen? You mean it makes the image show up bigger?

EDITED: Ah I just googled It and see exactly what you mean about integer scaling. I thought you meant it was a bad thing, but its a good thing. Im hoping most 1080p at 4k would look actually okay as it IS exactly double the resolution so integer scaling would work perfectly would it not?
 
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Thinking about it how does a 40" screen of the same resolution have the same pixel density as a 20" screen? Are the pixels twice as big? lols I think I might just be being a bit foolish how im thinking about it

EDITED: No sorry I am being silly, it would have twice the amount of pixels not twice the size to achieve the same pixel density wouldnt it. But surely then the image would be using 2 pixels on screen per 1 pixel on the image and therefore not showing it at its true resolutuon? i am being silly i think.
 
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This is what I am trying to understand I suppose, EsaT. How does image scaling actually work can anyone explain?
The maths of it is a bit confusing to me I suppose. Does a 4k screen have exactly double the pixels of a 1080? If it did surely it would have to take 1 pixel from source and show it was 2x2 pixels on screen? You mean it makes the image show up bigger?

EDITED: Ah I just googled It and see exactly what you mean about integer scaling. I thought you meant it was a bad thing, but its a good thing. Im hoping most 1080p at 4k would look actually okay as it IS exactly double the resolution so integer scaling would work perfectly would it not?

Viewing distance also comes into it too. I'd recommend watching this:

https://www.youtube.com/watch?v=Gnhv3WFnmH8 and this:

https://www.youtube.com/watch?v=ehvz3iN8pp4
 
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To be honest Fr0dders I am rather short sighted and don't really like wearing glasses when on the pc, so I prefer a smaller screen anyway that is just closer to my eyes. I have it pretty much a foot away from me and can see pixels on my 1080p screen. If I got a bigger screen I would want to move it further away so I could see it all, then my eyesight would be the bottleneck :(
 
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Considering im watching your 1080p video on my 1080p screen of your camera recording a 4k monitor playing 1080p footage...., looks pretty good bro. :p

Can your bluray player play Ultra HD Blurays? (4k i believe) Seems to be the only way of watching Game of Thrones for example, in 4k.
 
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Ah well it helps confirm that it still looks pretty good upscaled then. Not even sure if you can buy an ultra HD bluray drive for your pc? cant seem to see one on OC. Finding it strange how there never any 1440p native media content, like films or anything shot at that resolution. I guess they are always aimed at TV's and they kinda skipped 1440p.
 
Soldato
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Ah well it helps confirm that it still looks pretty good upscaled then. Not even sure if you can buy an ultra HD bluray drive for your pc? cant seem to see one.

I guess the reason why is that not that many people own monitors that can run at 4K resolution. Most have 1440p and ultra wides.
 
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