Sometimes you'll want to blur the edges of an object so it blends smoothly into its background - for example if you want to merge two bitmaps together without a sharp edge between them. Feathering is the answer

You can feather any drawing or bitmap but as an example I'm going to feather this photo of some flowers into a plain yellow rectangle that I want to use as a sort of frame. This is the picture with no feathering applied:

Now all I have to do is select my flowers image using the normal selector tool and then move the feathering slider until I get the right degree of blur for my requirements.

This is with the slider moved to the middle.

And with the slider moved to maximum.

If you want a non-linear rate of change in the feathering, then you can use the profile dialog, which you open by clicking on the arrow next to the feather slider. You can achieve some unusual effects with Xara's profiles (you can apply them to blends, contours, fills, shadows and transparencies). We recommend you simply experiment with the profile sliders until you achieve just the effect you're looking for.