Avoiding a motion blur 'shadow' around the still subject

[John Dudley]

I want to use motion blur to create a panning effect. I've tried selecting subject and then applying blur to the inverse. I've also duplicated the layer, then masked out the subject and applied the blur to the whole of the bottom layer. Each time I get some bluring of the subject around the subject like a sort of shadow effect. Is there a way to avoid this?

[D Fosse]

It all depends on how believable you need this to be. You're trying to simulate a very complex optical effect. There's no simple one-click solution.

You probably need to expand the selection a bit before masking. Off the top of my head I'm not sure if the masked areas affect the blur, but I believe they do, since the blur is on the pixel data in the layer. Then you need to punch out the subject completely before the blur.

Try different blend modes, perhaps on separate blur layers with separate mask outlines. If you use Lighten mode near the subject, you won't get shadows, but perhaps halos. Be prepared to do some local painting in the masks.

[Stephen Marsh · Accepted solution]

Select subject and copy the hero to a new layer. With the subject selection on the original layer, expand the selection and content aware fill or generative fill to "inpaint" the background where the subject used to be. This doesn't have to be perfect as you will be blurring the background anyway. This is just to remove any trace of the subject from the blurred image.

[adaptable_Glow5DB5]

Ah yes - I think that is a great solution - many thanks