Some monitors offer options that result in black bars on the side

Sorry, I can't help, but I just want to mention that years ago I had a laptop (a Hewlett-Packard something, I think) with a 16:9 or 16:10 screen, and it could output older games fine at 4:3 with the obligatory black side borders. Then one day it wouldn't show 4:3 correctly any more, and I couldn't fix it. I discovered via google that a software update (I can't remember if it was a Windows update, a GPU update, a Hewlett-Packard utility update, or whatever) had disabled the ability to show a genuine 4:3 picture, instead it was the 4:3 picture stretched right across the whole picture.

It turned out that there was a registry entry that controlled the laptop's ability to show a 4:3 image properly, and whatever software update had knocked out the ability no longer checked the registry key, instead it just ignored the 4:3 aspect ration and always stretched everything to fill the whole wide-screen. I remember that the update removed the registry key, and when I manually added it back, it made no difference.

In the forum posts I found about it, a few people tried various fixes but couldn't get the 4:3 function to work again. I'm sure I would have tried using the older software or removing the newer version, but whatever I did try didn't fix the problem.

There might be a (probably user made freeware) program to force 4:3 mode nowadays, and you'd probably be best off asking on the your laptop's official forum, in case such a program has to be specific to your laptop brand/model.

Good luck, mate.

Display aspect ratio control can be done at various points. The graphics card output signal, which is driven by the driver and OS and software.. and also many monitors expose an option to manually choose an aspect ratio (16:9, 5:4, 4:3).
Modern graphics cards don't seem to bother with sending proper aspect ratio info to the monitor during standard VGA modes, which often leads to stretched images during boot (unless using UEFI).

Under which environment are you trying to achieve 4:3? Native DOS? Win11 full-screen DOSBox?

Nvidia card?
Checked out the scaling modes in nvcontrol panel?

Kerr Avon wrote on 2024-10-16, 01:19:

years ago I had a laptop (a Hewlett-Packard something, I think) with a 16:9 or 16:10 screen, and it could output older games fine at 4:3 with the obligatory black side borders.

I'm fully aware that there are software controls for using the pillarboxed mode when running games that have a native 4:3 resolution on a widescreen display.

However, I am asking about games with a native 320x200 or 640x400 resolution, which were originally intended to be used with a 4:3 display and would so get a 4:3 image by the merit of being stretched, like DOS programmes.

For an example of what I'm looking for, there are games made with Adventure Games Studio (AGS), like Rob Blanc III*. They run natively in Windows and can be configured to use a resolution of multiples of 320x200. So this game runs in a window like this:

However, I can use DxWnd and run it in a 800x600 window (4:3 ratio), forcing it look like this:

But, (a) this is not the intended way of using DxWnd (I think AGS does not even use DirectX), and (b) some programmes that I've listed above do not work with DxWnd anyway.

I was wondering if there was a dedicated tool for achieving the same result. I can reformulate my question if it helps, are there tools to run Windows apps in fullscreen and/or windowed mode at any resolution specified by the user?

*Just to make sure I'm understood, I do not think that this particular game, Rob Blanc III, is intended to be run with aspect ratio correction to 4:3. I used this just as an accessible example of the effect that I'm looking for.

wbahnassi wrote on 2024-10-16, 09:20:

Under which environment are you trying to achieve 4:3? Native DOS? Win11 full-screen DOSBox?

I'm not talking about DOS at all, I'm talking about Win/Linux source ports of DOS games.

myne wrote on 2024-10-16, 10:14:

Nvidia card?

No

Have you looked at external scalers (e.g. Retrotink) for this? I suspect that in lieu of a video card driver solution (such as nVidia GPUs/drivers), you might need an external scaler with a high level of control over aspect ratios and resolutions.