Flou effect (aka Soft Focus), Gimp Tutorial
Soft Focus is an amazing effect to reduce skin defects or to give a "dream effect".
The Flou effect (also known as soft focus) is really raccomended in portraits photos, whether of humans or animals and is really easy to get with Gimp, The Flou effect softens the details and reduces the imperfections.
Applied on a female (or young male) portrait, reduces the wrinkles, makes it look brighter
and creates an angelic glow around the subject. In landscape
photography, makes unreal atmosphere as in a dream.
Now you will discover how to get a perfect Flou effect - Soft Focus with Gimp:
Open the photo that you have chosen, than duplicate the Background Layer. Find the Layers Window (press Ctrl+L if you can't find it), then Right Click on the Background layer and choose Duplicate Layer.
Increase the brightness of the photo, open Colors - Levels and set the histogram like the following one. These parameters are only guidelines, if you want you can change them as you like. Ensure to modify the brightness of the Background Copy Layer.
Now you must apply a Gaussian blur to the Background Copy Layer, open Filters - Blur - Gaussian Blur
and choose the right radius. The radius depends on size of the image, you have to see the shapes, but not the details.
Generally a radius between 10 and 20 could be a good solution, but I suggest you to experiment different values.
The last step for a perfect Flou Effect with Gimp, is merge down the Background Copy layer. You just have to set the Opacity to 40%, and then Right click on Background Copy - Merge Down.
Now the Flou effect is done, if your photo depict a face, is a good idea to erase the eyes in the blurred layer before merge down. Use the Eraser Tool of Gimp with a smooth brush and delete the eyes on the Background Copy layer.