Masking Artifacts after refinement, making the mask destructive vs non-destructive.

[Scott Prock]

Images are the results of using a selection brush to select the subject, then clicked refine and brushed over the edges of the hair. (simple basic masking refinement) Then chose new layer with mask as the output and got what you see. 

When you turn the mask off you can see all the junk, and where did all that come from and why? Masks are supposed to be non destructive, and this is most certainly destructive. 

I don't know what has changed, or if its something I'm doing wrong but about 6 months ago I started seeing issues with using mask refinements. I never had the time to trouble shoot and just brushed it off as something I was doing wrong. 

The zoomed in image shows the edge I didn't even touch with the refinement brush.

I've actually had to switch back to PHotoshop in order to get production work finished.

I have tested this on both a Macbook Pro 1st gen M1 and an 11'' M2 iPad Pro and get the same results. 

 

 

The original file as from Pexels ...


 

[Ldina]

2 hours ago, Scott Prock said:

When you turn the mask off you can see all the junk, and where did all that come from and why? Masks are supposed to be non destructive, and this is most certainly destructive. 

Scott, choosing "Selection" simply gives you a selection, which you can use any way you wish (create a mask, a spare channel, modify the selection, etc). Choosing "Mask" will apply your refined selection to a new mask on the currently selected layer. Neither of these choices do any "color decontamination". So, if you plan to do BIG MOVES, like changing background color or brightness significantly, you are likely to see more halos, color fringing, etc. 

"New Layer" and "New Layer with Mask" are usually used for compositing because these two options perform what Serif calls 'color decontamination'. These are sometimes better choices when you want to make big color or brightness moves and tend to result in better blending. If you choose New Layer, your original layer (the one used to make your selection) is hidden, and a new layer of just your selection is added above it in the layer stack. The fully selected portions are opaque, the fully unselected areas are transparent, and the partially selected areas have an Alpha value between 0 and 1 (i.e., semitransparent).

New Layer with Mask does the same basic thing, but preserves the original image and includes a mask (instead of forcing the unselected areas to be transparent). Those funky looking areas in the mask are where Affinity is doing some sort of color decontamination, so that's not a bug or failure. If you leave the mask intact, it seems to work pretty well, but if you turn it off, you get all those areas that Affinity is trying to 'color decontaminate'. I'm not fully aware of how that works myself.

I often choose "Selection", then save that as a spare channel. You can then load that to a Pixel Selection (with your pixel layer selected), create a mask manually, or you can go back into Refinement, and try another option, if needed. You can right click on the mask to re-enter refinement, then choose New Layer, or New Layer with Mask to try them out too.

I often tweak the mask manually using Curves or Levels, select the Alpha channel in Curves or Levels, and manually refine those semi transparent edges with a fair amount of latitude, expanding or contracting them, etc.The Curves/Levels Adjustment needs to be dragged onto the thumbnail of your mask, and you need to be sure any changes are made to the alpha channel in Curves or Levels. 

[carl123]

2 hours ago, Scott Prock said:

When you turn the mask off you can see all the junk, and where did all that come from and why? Masks are supposed to be non destructive, and this is most certainly destructive. 

Explained (in part) by one of the support staff in this thread...

 

[Scott Prock]

Thank you both so much. I was having a difficult time finding out what was going on. 
 

19 hours ago, Ldina said:

I often tweak the mask manually using Curves or Levels, select the Alpha channel in Curves or Levels

This is something I have been meaning to learn more about. I really appreciate the detailed reply.

I have used Affinity since the their beginning and remembered the masking ability around complicated hair to be far superior.

My current workflow involves removing the background on high school sports team photos. Often times there are students with wild hair and I hate how much haloing I have to work through using Photoshop.

The problem stems from needing to return the final result in .psd with an editable mask. 
 

So I had no idea this was an issue until I went to check the deliverables prior to submitting them and the masks were all trashed.

It makes sense now, as in I understand what the artifacts I see are and the why. 
 

I’ll have to adjust my workflow, and hoped I can have something that allows me to push through these type of edits faster using AP vs Ps

 

[AffinityJules]

I've always maintained that the selection and refine tools need some serious improvement.....stat!

But that's just me.

[Ldina]

@Scott Prock Glad it was helpful. I recently posted the following tutorial on masks and alpha on the affinity forum. Not sure if it will be useful for your workflow or not, but it does have some extra background information you might find helpful. Let us know if you have anything else we can help with. If you have a specific image that is giving you trouble, upload it and we can take a look.