On screen size vs screen size

[dsrtao]

Ignoring the technology actually used to create the display (CRT, LCD, plasma, projection, whatever), there are certain characteristics of computer displays that are commonly confused:

- physical screen size. Measured in millimeters x millimeters, or inches by inches, or approximated by a diagonal measurement (14", 16", 19"...) and an aspect ratio (4:3 if not otherwise stated, 16:9 or 16:10 if widescreen.

-logical screen size, often called "resolution", but it isn't. Pixel count in columns by rows: 640x480, 800x600, 1024x768, 1280x1024, 1280x768, 1600x1200, 1920x1080, 2048x1536...

- screen resolution. Measured in dots-per-inch or dots-per-cm. 65dpi, 72dpi, 90dpi, 120dpi, 144dpi... this is the result of dividing the logical screen size by the physical screen size.

When you ask someone what size screen they are using, you might get either of the first two responses. When you ask what resolution they are using, you might get any of the three.

How are they important? Well, physical screen size provides an angle of view. If you sit a little less than arm's length from a screen, a 12" screen is tiny, and a 20" screen is pretty nice. A 30" screen is almost overkill... almost. But given a particular physical size, higher resolution (or a larger logical screen size, same thing) is always better. Due to stupidities in the way windowing systems used to handle these things, people often have the notion that a higher resolution screen means everything gets smaller, and thus harder to see. But a modern windowing system renders text and scalable graphics in the same physical size regardless of the logical size, so things remain the same visible size, but more dots are used to draw them, and so they are easier to read -- text is smoother, graphics have more detail.

At home, I use two 17" monitors running at 1600x1200. This doesn't feel like enough visual space any more, although it is generally enough logical space. At work, I have a 19" monitor now running at 2048x1536 (Until Friday it was at 1600x1200, which felt a little loose). This is also not quite enough visual space -- and now it doesn't feel like enough logical space, either. What to do, what to do...

Comments

[metahacker.livejournal.com]

Viewing distance is usually ignored, but gets more important as you get older. Obviously it has a linear effect on screen dimension and effective resolution (pixels per visual arcminute is probably a good number). Not sure if you've started to notice changes in your distance vision, but it's definitely becoming relevant for me. This means that e.g., a 12" display at 24" is NOT the same as a 6' display at 12', and really not the same as a 3" display at 6". I wonder if we'll ever get displays which work by transmitted, rather than emitted, light, and therefore allow "focusing" of outgoing light to adjust the effective distance. (In-eye displays work this way, I'm told; never heard of it for wall displays/etc.)

Super-nitpicky: dpi != ppi... ;)

Contrast and lighting drastically affect usable resolution. I prefer a sharp 800x520 with a hard-edged font in a neutral environment, over a blurry 3000x1800 in a dark background (e.g. movie theatres) for reading text.

By your definitions the only "modern" OS is OS X, which allows you to set the screen resolution (ppi) and have everything scale accordingly -- everything is scaled before it is written to the visual display anyway. (Or have Gnome/etc. caught up with the 21st century yet?) However, since we are usually viewing things close to 1x the resolution (e.g., .), scaling ain't free; artifacts of scaling dominate. Hence I still prefer pixel-based displays for content, though I'm willing to use scale-independent displays for screen management and notification (e.g., scroll bars).

Mouses are often the last thing to respect screen resolution. This is extra annoying!

[dsrtao]

Contrast and lighting drastically affect usable resolution. I prefer a sharp 800x520 with a hard-edged font in a neutral environment, over a blurry 3000x1800 in a dark background (e.g. movie theatres) for reading text.

Sure, but apples and oranges. In the context of the same display device, an 800x600 vs 3000x1800 probably has a tradeoff of refresh rate more than anything else.

Or have Gnome/etc. caught up with the 21st century yet?
Mostly. If you take the time to set it up -- mostly, but not entirely "point-n-click" level -- you can have all your fonts and all the desktop-supplied widgets drawn at the physical size you desire. Changing between them on the fly is slightly more difficult, but doable.

The major difference when I changed from 1600x1200 to 2048x1536 on my work monitor was noticing that GIF and JPEG in Firefox were smaller, but SVG and fonts and widgets and such were properly scaled.

Assuming you've got a modern $14 mouse -- USB and optical are the required characteristics -- adjusting the movement rate is pretty easy. It's so individual that it was already at the point-n-click level.

[metahacker.livejournal.com]

adjusting the rate is pretty easy

It's the built in trackpad -- and adjusting under winXP is anything but easy or precise. You have the usual stepped choices of Granma, Slower, Slow, Slowish, Too Fast, and Rather Way Too Sensitive. And since I'm switching between devices when I undock/dock the laptop, I can't even leave it at one setting -- the dock's mouse and the built-in trackpad (and/or pointing stick) are all different sensitivities. It doesn't seem to account for res at all, either -- the docked monitor is significantly higher ppi than the built-in screen, but of course WinX doesn't care.

Ah, modern OSes. I wonder how VMS handles this? ;)