Circular images in darktable

[Juha_Lintula]

How can I create a circular image in darktable? De facto a rectangular image with solid color frame and a round “hole” for the image itself. I know that with GIMP or any other pixel based editor this can be done easily, but that would require exporting the image and processing it in another tool. So I was wondering could this be done in dt.

I tried retouch module, but I got a round black hole in my image, and there was no way to invert the mask.

Censorize module produced nice soft background, but I couldn’t make it solid black/white.

Best I could find was vignetting module, and moving the brightness slider to min/max. The only issue there is that you cannot draw the circle, but you need to define it based on the dimensions of the image. Also, if you change your crop, the circle will keep it’s relative position to the image, not the position where it was placed.

Any other suggestions?

[Dave22152 (Dave Goldberg)]

Colorize module, set to solid white with a circular mask in the center?

[EspE1]

I also thought of colorize, but would try if it would work to combine that with another image overlay with composite module with a mask.

[Terry (Terry Pinfold)]

I am not aware of any way of doing this in DT, but I would export to GIMP as an xcf file and do it there as you are aware. I would then save as a tiff or png to retain transparency to get a ‘true’ round image taht could be used for a logo or whatever. I really like the new ability to export XCF files when GIMP is required in the editing process.

[EspE1]

If you just want a black frame, you can use exposure module and make a drawn circular mask, and invert it. Set exposure really low and you get

If you need other colors you can used colorize module, with similar inverted drawn circular mask and get e.g.:

EDIT: I forgot to make the colorize mask solid. That could have been done with the source mix slider set to 0 %.

[EspE1]

I also used retouch to fill an image completely with a solid color and saved the file. I then activated composite module in the image with the bird,
(-- which I have downloaded from play raw once, don’t remember the photographer). Then I “imported” the color file into composite and again used a circular drawn mask that I inverted.
This also worked to the extent that the bird image got circular with a frame around it – but for some reason the solid color image then comes through without the fill color, so the frame is from the other picture:

Don’t know if this latter phenomenon is a feature or a bug, but I tend to think a bug since the color file present itself as such in the thumbnail image within the composite module.
But if you have a file with a solid color, this method also can be used.

EDIT: The character of the border of the circular mask is adjustable as for how hard/soft it shall be etc, as is normal for masks in general.

[priort (Todd Prior)]

Dave nailed it…colorize will give you any color or black or white…just set the mix to zero… and mask…

[Dave22152 (Dave Goldberg)]

Here’s an example using colorize, saturation 0%, lightness 100%, source mix 0%:

You could create a frame with a second instance set to black (lightness 0%) and a slightly larger mask:

But you could have issues with pixelated edges around the frame, so GIMP might give you the best result.

[Juha_Lintula]

Thank you all. I hadn’t never used the colorize module, so wasn’t aware of it. Thank you all for the help!