Good/easy ways to letterbox/pillarbox digital images?

Let’s say I have some picture I want to use as my desktop wallpaper that has a 4:3 aspect ratio. My monitor, as one might expect these days, is 16:9. Cropping and/or zooming into the picture is the obvious solution, but in this case the subject would be awkwardly cropped. So, I’d like to mat or pillarbox the image in some way to make it look good (or at least better than the default teal of my desktop).

Are there any good guidelines or procedures for what looks best? I could imagine doing something like blurring and stretching the original and putting the picture on top of that, but I can’t get results I’m happy with. Should I change the saturation and/or value of the result? Is there some good algorithm that would tell me the best color to use? Twitter does something similar on their phone apps—should I try to copy what they do, which seems like most common color darkened and muted? Are there any apps or websites that do this?

(I hope all that made sense—I tried googling, but kept on getting hits for physical mats and wallpaper.)

I don’t know what OS you are using, but there an option in Windows 10 to “Center desktop image” when choosing a wallpaper. I believe that will automatically fit the image with bars on the sides.

I am using Windows 10. It does, but the bars are just the color of my background (more of a minty blue than a teal right now). I’ve also got FastStone Image Viewer, which will crop, zoom, and add bars as well.

I might not be explaing it well—I’d like to know a way to pick the color of the background (and, therefore, the bars) that would look good. I’m also competent enough in GIMP and to do something fancier, but I don’t know what that fancy thing would be. Does that make (more) sense?

In GIMP, just add a new layer with the size of your resolution/desired image size, set the color of that layer to your desired color.

Then resize the original image layer, and there is a “center image” option during resize. Merge your layers and overwrite or export.

You might think that I could figure out what color I should use, but I really can’t.

I feel like it (1) should depend on the picture itself and (2) I should be able to come up with a process to choose that color that works most of the time. To be fair, plain black does work a fair amount of the time, but shouldn’t I be able to do better than that?

Ohhh, it’s the color selection you are looking for… Apologies, I didn’t pick up on that.

What I usually do is make a copy of the image. Distort and scale it to the monitor size and aspect ratio. Then blur the image. The blurring hides the distortion but the blurred image has the same colour palette as the original. How much blurring depends on your taste.

Then take the original (undistorted, sharp) image and place it centrally over the blurred copy.

Depending on my mood and the image I might place the original image off centre because I am an artistic type. I might give it a pin (thin) border in black or white or a colour from the image. There’s also the always popular drop shadow effect.


Plugins exist that fill in missing parts of images with plausible content, but I do not know if there is a ready-to-use GIMP plugin for that, or what the minimum specs would be for a graphics card to handle it.


Eh. To me, finding the proper color for letterboxes/pillarboxes is simple: the answer is always “black”.

For watching videos and such, I agree. But when things can actually appear on top of the pillarboxes, then I don’t want black.

I played around with blur + border, as @TCMF-2L suggested. I think the border helped a lot, personally. Thanks!

I also have access to Python and Pillow. I should be able to come up with something that finds the most common color, darken and/or desaturate that color, and add boxes in that color to the photo. (How much to darken/desaturate is the question, of course—though I can guess Darren’s answer.)

I thought something like this would already exist, but maybe it’s more of a niche need than I thought. Or it depends on personal taste more than I thought. Or maybe five lines of code don’t need to be turned into a standalone program.

If your comfortable with Python and writing some code, take a look at the colorthief module. It can return the dominant color for an image along with a variable length color palette of colors found.

That’s nice and simple and does what it says, more or less. (I remembered Pillow being fairly opaque, so I wasn’t really looking forward to digging back into that.) Thanks for pointing it out!

It finally occurred to me that advice for selecting the colors of mats for framed photos would apply to my situation as well. I’ve found a couple of good links, which suggest stuff that seems right to me but I couldn’t put into words, like using a background color for the mat to accentuate the foreground, using a color that’s one tone lighter than the darkest part of the background for dark mats, stuff like that. So I’m happy with what I’ve got now.