Selection brush problem while trying to remove a background

[Anonymous_]

Hi, I'm new to Affinity and I'm trying to remove a background from an image. I used the selection brush to select my subject that I want to keep in while removing the background. When I remove the background, it leaves some area outside the selection (shown in the second pic). Has anyone had an issue like this before or know how to fix it?

 

Edited November 26, 2023 by Anonymous_

[NotMyFault]

This can happen especially when you use "refine selection". If you need a hard edge for your selection, don't use refine selection.

 

[Anonymous_]

Great

1 hour ago, NotMyFault said:

This can happen especially when you use "refine selection". If you need a hard edge for your selection, don't use refine selection.

 

Great thanks

[Granddaddy]

My experience in extracting people from complex backgrounds is that this always happens. I always have to clean up the mask produced when the selection is output.

You must also clean up the portion of the mask that exposes the subject itself. There is always spillage (or whatever the appropriate term might be) onto the subject itself.

Just as you clean up the mask by painting on the mask with white outside the subject, so you must clean up the mask by painting on the mask with black over the subject itself to ensure the transparent area is fully transparent. You can alt-click on the mask icon to see it in black and white.

Since I am selecting subjects with hair flying around, I can't avoid using Refine Selection so far as I know. That's what all the tutorials show that I've seen. Some suggest just wiping out the loose hair and drawing in your own version with a suitable brush. That's beyond my limited artistic ability.

Various solutions have been proposed in tutorials and in these forums for dealing with masking artifacts. I only do a few of these extractions each year, so I haven't studied the solutions in detail. Perhaps others with more experience will add to this thread.

[NotMyFault]

If you want a clean mask for that specific file, I would use the pen tool and create a vector mask (curve layer). When done, add a little bit of Gaussian blur via layer fx.

Selection brush and all other pixel based tools won’t give pleasant results, the contrast in the image is too low.

[Anonymous_]

Thanks for the input guys. I'd say for now for me it's better to use the pen tool to cut out more complex images and wait until the guys at Affinity improve the selection brush in the future.