Windows 7: How to blank the screen (or reduce to a color) with a shortcut?

W7 Ultimate 64bit.

I've just started to play Tomb Raider, Game of The Year edition.

(Yeah, I know it's an antique game but I've always been a late developer)

I don't want to play Tomb Raider full screen on my 24" monitor, so I have it set to display in a window of 1440 x 810.

My question: Is there an app or a shortcut that would give me a black (or whatever color I might choose) background to my windowed screen?

So when my game window opens, I can hit ......(whatever) and see my game on a background of my choosing, instead of my desktop display.

Have I put this right? Can my colleagues on W7 understand the question?

Thanks, guys and girls :-)

What GPU do you have, depending on how it is set to handle scaling it can make the aspect ratio of that resolution in fullscreen but have it in the center of the screen with black borders around it.

Thanks, rvcjew. The card is an NVIDIA GeForce GTX 960 4 GB.

I asked the question because somewhere, somewhen, I saw a guy offering a little app he'd written that did the job. But I can't find it again.

Try it with no scaling picked then run the game in fullscreen at the low resolution. Can also try aspect ratio like I have, as well as setting the override if it does nothing.

Thanks, but I don't want to run the game full-screen. It's too big on my 24" Asus ProArt monitor. Like sitting courtside at a friggin' tennis match.
Maybe my peripheral vision isn't 100% - dunno. But I much prefer the game to be windowed.

This guy has partly done the background thing (and, of course, you can up-size it with old F11 trick):
https://www.yofla.com/black-screen/#

TR runs on the partial blackout, but at his full screen (after pressing F) I can't access the TR game controls.

If you pick no scaling it wont use the whole screen it will make it like this so it's windowed in the fullscreen if that makes sense.

deleted, sorry wrong thread

Thanks, rcvjew, I'll try your suggestion.