Artturi

Masked gaussian blur sadly seem to be producing ghosting effect where the not blurred object is partly visible behind the blurred one and it doesn't look professional. 

Hi @Artturi  I can't put my finger on what's causing those cyan artefacts/highlights, sorry – your file opens and displays fine on my Mac system.
Could this be one of those your-graphic-card-driver-needs-updated scenarios that sometimes seems to trouble Windows users?
What version of Affinity Photo are you using?

I would like to be able to edit / revise a mask after creating it, using curves or levels .. ideally as an adjustment layer specifically for the mask, but I'd settle for simple adustment of the mask, as in Photoshop. I routinely use the image itself as a mask, for example to protect highlights, and it's essential to be able to adjust the tonality of the mask while editing.

@Artturi please try with the beta of photo app. Do you try to save the files on a network share or in the cloud? Please tell more about the hardware you use.

Hey, thank you. I already found the way to do that, but those definitely are helpful to understand even more about this topic! :)

I would like to use the same workflow I used to work with Photoshop. When I open for example Jpeg image in the editor, I can edit it with the same tools as I edit the raw images. 

Wow, amazing, this small trick made my life so much better. Thank you!