Using a gradient mask to blur part of an image

[spinsheet]

I have a photo and I would like to blur the bottom of the image while leaving the top of the image sharp, similar to limiting the depth of field by using a large f-stop. I created a gradient mask and then used Filters > Blur but it is not working. If I choose the layer that I created the mask on and choose blur, nothing happens. If I choose the layer (background) under the mask then the whole image blurs.

Can anyone offer a suggestion?

Thanks.

[ofnuts]

Try this:
- make sure your original layer has an alpha channel
- duplicate the layer
- apply blur to the copy (which is one top, normally)
- add a layer mask to the top layer
- put a black-to-white gradient on the layer mask, with the white where you want things blurred.

For added points, using the various color transform tools (in particular, the "curves" ones), you can change your linear gradient to something else, and so control how and where the blurring is applied (and see it in real time).

[spinsheet]

That worked great.

Thanks!

[noelb65]

Worked nicely for me too, thanks