The directions for how create a gradual blur in Photoshop Help are unclear to me:
To create a gradual blurring (none at the bottom to maximum at the top), create a new alpha channel and apply a gradient so that the channel is white at the top of the image and black at the bottom. Then select the Lens Blur filter and choose the alpha channel from the Source popup menu. To change the direction of the gradient, select the Invert check box.
I've tried to follow the directions for creating an alpha channel in Photoshop, but I just end up with an opaque channel in the channels palette. It doesn't allow me to apply a gradient in the channels palette, and of course it doesn't show up in the layers panel.
So how do I do this? Please include all the steps that a rank beginner would need, as I will most likely miss something otherwise. :)