Rontarrant is exactly right. If we have a screen that’s twice as many screen pixels wide and twice as many pixels high – compared to a standard “HD” monitor – then if the pixels are going to LOOK the same size, the panel will have to be physically twice as wide and twice as high.
(FYI, for those new to all this, UHD (3840x2160) is exactly twice as many pixels wide and twice as many high, as full HD (1920x1080).)
If we’re planning on using this UHD panel at the same viewing distance, then we will want the pixels to be about the same size as what we’re used to. That has to mean a panel that’s 4x the size of HD, or typically about 42 inches wide. That’s a TV diagonal of 48 inches.
If we want to sit farther back, then the pixels themselves have to be BIGGER.
For example, for a panel at 30 inches viewing distance to look the same (i.e., to be equally readable, assuming we can focus at this distance) as HD at 24 inches, it would have to be roughly 55 inches diagonal. This sounds pretty cool – more room for keyboard, nice big screen – but when we actually put a 55" TV on the desk, 30" from our keyboard, it’s gigantic. Half of our extra real estate is UP, and it’s probably not quite as much fun to use as we’d like.
What most people are doing is getting UHD on a much smaller scale, and the tragic truth of this is that although the picture is sharper (if we stay 24" back from it), we can’t USE all the extra pixels the way we’d like. To do that, somebody has to design a completely different set of proportions for all the GUI elements – text, menus, icons, borders, pretty much everything. And that’s not something that can be done with some settings. (We can lower the effective resolution of the panel, or ask the OS to double all the pixels, but then we’re just simulating a non-UHD display and wasting our money.)
Allen