Refine Selection keeps changing the selection after creating a layer

[Audiocage]

This is really frustrating. When in Refine such, the overlay shows the selection and it looks great. However, when I commit the selection to a Layer With Mask, the mask actually alters quite a bit by creating a lot of semi-transparent border pixels. As far as I am concerned it should not change the selection at all, otherwise what would be the point in the selection? See the attached.

That said, is this a bug?

I've tried a number of different options but the results are the same.

Regards

[carl123]

Is this on all images or just the one shown?

[Audiocage]

It wasn’t doing it on follow on images. All the images I was working on were Stacks. 

[carl123]

Can you upload an example Affinity document where this happens?

[Audiocage]

Yup. I reduced it considerably and tested that masking still exhibits the problem.

steps to replicate the issue:

1. Use Selection Brush Tool to select the sky.
2. Click to Refine and note that the edges of the building are clean and not selected.
3. Select to Create a Layer With Mask
4. Then, right click on the mask and select Refine Mask. You should see the refine process creeps into the building with semi-transparent pixels and that it is no longer a clean edge as it was before.

sample 2.afphoto

[Audiocage]

 

Here are a few videos showing the problem on 2 different photos.

[NathanC]

Hi @Audiocage,

Can confirm I've replicated this issue and logged it with the developers. As a workaround when refining the mask try unchecking 'Matte Edges' and see if that prevents the unexpected pixel creep.

[lepr]

@Audiocage

Not a bug, in my opinion, but the logical consequence of the refinement options that were enabled. You used 'Matte edges' and the 'New layer with mask' output option which dilates the colours of the unhidden region into the hidden region of the new layer. If you disable the mask so you see all of the 'new layer', you'll see why a subsequent refining of the mask with 'Matte edges' will cause the mask to creep so dramatically.