You can use focus blur plug-in for that purpose.
Windows binaries can be found at Michael Schumacher's page as fblur
Jarlath Reidy wrote:
> I want to create a depth of field effect on an image which is currently
> well focused all around.
> I would like to be able to apply a blur that gets more intense as the
> distance from the subject increases.
> I had thought that I might be able to create a layer with a radial
> gradient and apply some effect to it but I haven't been able to figure
> this out.
> The only mention of Depth of Field in the Beginning Gimp book I have is
> in relation to photography as opposed to editing.
> Can I achieve this effect?
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