Create a collage/montage using G'MIC under GIMP


I am a newbie to G’MIC (latest stable release on Ubuntu) and my first approach to this powerful tool is to create a collage.

I want to have a (horizontal) picture with a frame ratio of 3:2 to be printed as a photo (10 cm x 15 cm). I have 4 photos to be placed on the final photo, and I want some space (a small 5th plain) for text.

I have managed to do this using G’MIC. What I do not understand is how the overall frame ration for the final picture works. E.g., if I only consider the 4 pictures I can use “H(V(0,1),V(2,3))” or “V(0,2),V(1,3))” to achieve the same order, but the frame ration is a different one.

But as I wrote, I want to achieve a final picture with a given frame ratio and resolution (3:2) and a resolution so it can be printed as a collage photo.

I am aware that this might be a silly newbie question. But amybe someone could still gelp me out with this?



@Eriol Welcome to the forum! Could you please provide an example? Or at least a rough sketch of what you would like to achieve? E.g. I don’t understand where you would like the text to be.

Okay, sorry, I was unclear:

The most important question is:

I have a target format - I want to have a horizontal graphic in 2:3 aspect ratio that I want to print as a photo print. So the result should be a picture with e.g. the size 2000x3000 pixels, or 4000x6000 pixels.

I have 4 photos (in high resolution) that I want to place on it - two are upright and two are landscape. (And /somewhere/ I want to have space to write a text - this could be on another small image layer I place where there is space).

The arrangement is ideally like this:


And possibly to the right (or left) of it a layer from top to bottom for the text. If that works. If not, then I leave the text out of this and put it into the final image.

At first I only experimented with the 4 photos. I managed to arrange the photos in the desired order horizontally and vertically. But what is completely unclear is how I can influence the result in terms of the size of the pictures and the size of the final result.

When I place the 4 images, the result is almost square. That would be OK in principle, because I could then place the text layer on the side. But at the moment this is all completely random to me.


I think you try to consider too many constraints at the same time.

The montage filter in G’MIC is not able to target a desired aspect ratio. It actually doesn’t modify the aspect ratio of the input images but resize them according to the specified montage scheme.
For instance, if you try to create an horizontal montage from two 2:3 images, of size 2000x3000 (portrait) and 3000x2000 (landscape), with layout “H(0,1)”, you’ll get a result of size 4333x2000, which is absolutely not 2:3.
Same if you append two horizontal montages like this, but vertically. You’ll get a 4333x4000 image, still not 2:3.

I guess that you’ll probably have to crop your images in a way or another to ensure you get the desired aspect ratio. And honestly, knowing exactly what crop coordinates to use is probably not easy to guess :slight_smile:

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Like this?

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Exactly! And the text would be left or right of it.

I will play with the settings and my photos a bit and indeed crop them as far as I can.