[Photo] Invert mask differences

[sankos]

Hello,

 

I'm quite puzzled by this:

 

I want to create luminosity selections/masks. 1) I Ctrl-Shift-click the Background layer thumbnail and save the selection as a separate Lights channel; then 2) I invert the created luminosity selection and save it as a separate Darks channel.

 

Then I do a similar thing in Photoshop Elements and make masks from the selections to compare if I get the same thing in PSE and Photo. The Lights (luminosity) mask is the same, but the Darks masks are different -- Affinity makes it more muted, the inverted black patches are more muted/greyish, and 50% grey patches are considerably darker than in PS.

 

Can anybody reproduce this? Is this a bug in the Invert selection command? When I compare the inversion of a normal pixel layer, the results are the same in both applications.

[sankos]

Some further testing: when I make a black-to-white gradient and select Luminosity (the Lights selection), AP gives me a 50% selection, whereas PSE gives me something like 70%. I'm not sure what might be the cause of it. So which is the correct luminosity selection?