[Affinity Photo] View a channel without alpha?

[bitinn]

Hi,

When trying to view a texture with channel packing (where alpha is not transparency, eg. 4 channel each represent some grayscale image), how can I tell Affinity Photo to not display a channel with alpha applied?

My problem: I am viewing the Blue channel, but AP still use the Alpha channel to mask the output. Like following (the shape is from Alpha, the grunge is from Blue channel, I want to view the Blue channel alone):

 

 

The channel panel:

 

I tried to find a profile in AP that treat RGBA/8 PNG as Linear or Raw, but there isn't one.

 

So is what I want possible in AP?

[bitinn]

I am sure this was asked before, but I couldn't find an answer, is there no way?

[myclay]

Hello bitinn

sadly there is no direct way, but you can trick it to show each channel
within the Channels there are two RGBA stacks available, the composite one (composition of all layers)
and your channels per layer, you have to separate the Alpha from your Layer for it to work.

1. Create a spare channel and then a Mask channel from your Alpha - the Layer Channel (not the composite one)
2. Fill your Layer Channel Alpha
now you can at ease edit the RGB channels while you can toggle the alpha mask(the one above your Layers) on and off.
3.To finalize the Layer, right click on your Spare channel and load it into the Layer channel alpha.

To be able to edit your alpha;
you would have to either strg click on your mask layer to put it into your Pixel selection
or to right click on the spare channel to load it into the pixel selection.

For Packing Textures including the alpha channel, something else like channel shuffle is a necessity.

an example file with enabled history is attached.

 

temporary solution_v3c.afphoto