Masking a Group Causes Colour Fringes due to Passthrough Blending Mode

[- S -]

This is an old issue – I even commented on it five years ago.  However, I never figured out what Affinity Photo is actually doing.  Affinity Photo is obviously applying some sort of blending mode, but I don't understand what blending mode it is actually applying – or why it is applying it.  I can't think of any reason how this would be considered normal operation; there are no real world scenarios where this behaviour would be expected.

The attached test file contains a single pixel layer, which is in a group, and a mask is applied to the group.  In a real world scenario, there would be more layers in the group and therefore the mask would be masking multiple layers in the group, but for demonstration purposes I am only using one pixel layer in the group here.

The default blending mode for groups in Affinity Photo is Passthrough.  With the Passthrough blending mode, the mask does not work as expected (see below screenshots).

Screenshot A:  The mask that is masking the group is just a straight horizontal line running through the centre of the image. The expected result would be the group mask just revealing the pink layer (Fill layer) below.  However, as can be seen in the screenshot, the Passthrough blending mode causes odd distortions, colour shifts and fringes.

Screenshot B:  With the group blending mode set to Normal, the mask works as expected – the straight horizontal mask running through the centre of the image just reveals the pink layer below, with no odd distortions, colour shifts and fringes.

 

Original File:

Test 01.afphoto

 

[- S -]

Below are similar images to the original post, just with the mask shifted up slightly.

Screenshot C : 

Screenshot D :

 

Original File:

Test 02.afphoto

 

[NotMyFault]

Probably related (and unanswered since a long time )

 

[Dan C]

Hi @- S -,

Thanks for your report!

I can confirm this issue is already logged with our developers, though the previous example files provided do not show the issue as clearly as your document - so I will be providing this to our developers now, alongside 'bumping' the report with them.

I hope this helps

[- S -]

1 hour ago, Dan C said:

Hi @- S -,

Thanks for your report!

I can confirm this issue is already logged with our developers, though the previous example files provided do not show the issue as clearly as your document - so I will be providing this to our developers now, alongside 'bumping' the report with them.

I hope this helps

 

Thanks.

 

[- S -]

This issue is still present in Affinity Photo V2.  See here:

 

 

[Arno A]

I see, thanks for the workaround. I will use "normal" mode for now.

[Affinity Info Bot]

The issue "Masks on groups with Passthrough don't composite correctly" (REF: AF-2951) has been fixed by the developers in the latest beta build (2.6.0.2805). The fix is planned for inclusion in the next customer release.
Customer beta builds are announced here and you can participate by following these instructions.
If you still experience this problem once you are using that build version (or later) please reply to this thread including @Affinity Info Bot to notify us.