KoreaBeat: I like to play in the original aspect ratio, so for Dosbox games I set aspect=true and set fullresolution to 1280x960, which is the largest integer multiple of typical DOS resolutions that will fit on a 1080p screen. If you have a 1200p screen you can go with 1600x1200, or 1,920x1440, if you have a higher-res monitor. Those resolutions would fill the screen vertically while keeping the right aspect ratio.

Then for the output, I usually go with openglnb because I think the fuzziness it introduces looks more like the CRTs we all used to play these games on. But opengl looks great too with the razor-sharp pixels it produces, so I like that sometimes too.

Ultra_DTA: Thanks for the input! So some of these games will be in 4:3 right even in fullscreen? That happens to me when I play Redneck Rampage. Or do I just not have it set to the proper resolution? I'd rather have the real aspect ratio like you said, than have it stretched. I use 1080p.

KoreaBeat: Yeah, if you follow my recommendations above then you should get a pillarboxed, 4:3 screen, as long as your graphics drivers are also set to preserve aspect ratio for non-native resolutions, which they probably are. Redneck Rampage came out in the 4:3 era so it should have black bars on the side. Is that what you have right now? Do you know how to edit the Dosbox config?

KoreaBeat: So your PC monitor is 1080p? If you are getting a stretched screen on your PC but not your TV, I assume your graphics driver is not set to preserve aspect ratio. If you have an Nvidia card, you can go into the Nvidia control panel to change this setting in the "Adjust desktop size and position" section and then select "no scaling". I don't have an AMD card but there should be something similar.

Also, in my opinion the best results come from editing the Dosbox config to set aspect=true, output=opengl, fullresolution=1280x960, and scaler=none. That should look just about perfect for games in 320x240 and 64x480 resolutions. There will be black bars on the top and bottom, preserving the aspect ratio exactly.

KoreaBeat: I like to play in the original aspect ratio, so for Dosbox games I set aspect=true and set fullresolution to 1280x960, which is the largest integer multiple of typical DOS resolutions that will fit on a 1080p screen. [..]

phaolo: I like the original aspect too! I hate those stretched blurry images and I don't mind too much the black bars.
I would even play with the original max\common resolution, if I could (silly LCDs!).
But isn't 1440x1080 the largest integer DOS res multiple on a 1080p screen?

Ultra_DTA: Yea I have AMD, there is something called a "catalyst control center" from AMD. I'll have to do a bit of research since the scaling options, fullscreen or centered, are blocked and won't let me change them.

Ok, so will playing them in fullscreen or in bigger windows stretch the image at all? It seems that the smaller windows make them look better.

KoreaBeat: Playing in fullscreen 1440x1080 does stretch the image, since that's a 4.5 multiple of 320x240, but you might not really notice it. Especially with Redneck Rampage, I nevr played but since it's a fairly late game, I believe you can set the in-game resolution to 640x480 and then that will only be a 2.25 multiplier.

The smaller windows look better because the pixels just seem smaller. It's all a matter of preference.

Ultra_DTA: Also, I'm not sure how long you've been playing, but when DOS games were originally played on the old crt monitors, how did they look?

KoreaBeat: No problem!

I started gaming on PC in about 1993, more or less the golden era of DOS in my opinion. A CRT is different from a modern LCD in several ways, one of which is that it doesn't have a native resolution, so it can displayer many different 4:3 or 5:4 resolutions and fill the screen with no need for stretching. An LCD has a native resolution and has to apply a scaler to stretch the image to fill the screen, unless it is set not to do so. In greatly simplified terms it applies a multiplier.

So a 320x240 screen could be multiplied to 640x480 or 1280x960 while preserving the aspect ratio exactly, because those are integer multipliers. So if the game's original resolution is 320x240 or 640x480, IMO it is best to go with a centered 1280x960 screen. Then there's no stretching. You should still keep aspect=true to be fully certain.

Beyond that, CRTs had a slight curve to them that the standard build of Dosbox cannot reproduce. Also, output=opengl will produce a very sharp, clear image compared to a real CRT. output=openglnb will produce a softer image that IMO looks more like an original CRT. But those sharp images really do look nice.

Consoles played on TVs output all kinds of resolutions and I've never really gotten a handle on all that.

F4LL0UT: Not that different, really. CRT TVs from those days created a quite different image than modern screens (as illustrated by this image) but CRT computer screens from the DOS era usually already created a crisp image (unless your screen's settings were really messed up). The screens were convex, though, so the image was kinda distorted, particularly in the corners (as illustrated on this pic - note that the blurriness and noise on this pic imitate TVs, not computer screens).