Outline of a selection

[rich2005]

(05-26-2023, 08:32 AM)prandus Wrote: But my problem is mainly, in fact, the blurring of the background.
With "Gaussian blur", there is the problem of the halo; it is avoided with "median blur"; but I find the result less natural. 
Maybe I'm too demanding...

Not too demanding, as usual all sorts of ways to accomplish anything in Gimp.

The important bit is the foreground extraction. Worth spending some time on it. I did use FG select tool here, but still needed to (quickly) go around the edges of the layer mask to tidy up the border. 

   

The gaussian blur 'halo' is caused by the difference in colour betreen the flower and the dark background. Other images will have different problems. In this case just fill the area of the flower with black.

   

Then the separate background layer is blurred with the separate foreground layer on top.

   

[prandus]

The subject was difficult (edge of the flowers). But, following your advice, I managed to get something satisfying.

Thank you for helping me progress.

[Ofnuts]

(05-26-2023, 08:32 AM)prandus Wrote: Thank you.

Indeed, there are several methods to clip the foreground; some faster than others, depending on the image.

But my problem is mainly, in fact, the blurring of the background.
With "Gaussian blur", there is the problem of the halo; it is avoided with "median blur"; but I find the result less natural. 
Maybe I'm too demanding...

Did you try the Lens blur with a focus map?

   

[prandus]

This is indeed an interesting effect for certain types of photos, such as landscapes.