Exponential degrade or similar effect to this one

Question

I'd like to reproduce a similar effect to the one on this image (in Gimp if possible). The borders can be extracted but there's some sort of exponential degrade at the bottom. How could I go about this?

Answer 1

I think you are wanting a Gradient Fade.

This link shows you how to fade to another image but you can just as easily fade to a solid colour (grey in your case)

http://emptyeasel.com/2008/08/29/how-to-create-a-photomontage-in-gimp/

Answer 2

An easy way to do this that will give you flexibility in the background is to use a gradient in the layer mask.

1. Add layer mask to the image if it doesn't already have one by right-clicking on the layer in the layers tab (default for flat images is named "Background") and select "Add Layer Mask"
2. Choose the default white mask (full opacity)
3. In the layers tab, click on the new mask - it's directly to the right of the layer preview rectangle
4. Back in the image window, use the gradient tool to draw your fade. You will notice the image fading to transparency. If you create a new layer under this, you can play around with how the fade should move, whether to a solid color, staying transparent (PNG-only for the web), or to another image.
5. You can apply the layer mask in the end if you want. It will collapse the two into one layer. Right click again in the layers tab on the layer and select "Apply Layer Mask"