Editing spare channel

[chrisb123]

I would like to edit my spare channel so that is black or white, it is currently greyscale

I know I can click on it and start painting, but I'd like to add a filter so the dark grey bits turn black and the light grey turn white
I cant find the correct filter to do this
 

[ashf]

This is kinda pain-in-the-neck in Affinity.
You have to create a layer from the spare channel.

1. Create an empty pixel layer and select it.
2. Right-click the spare channel and "Load To Pixel Alpha."
3. Right-click the pixel alpha and "Create Grayscale Layer."

[chrisb123]

After the right-click on the alpha channel Im not seeing a "Create Greyscale Layer"

Also how do I use a filter to adjust how I then turn this into a pure black and pure white image to be used in the channel

[ashf]

Not the Composite Alpha. It's the "Pixel Alpha."

[ashf]

After you edited the grayscale layer, do "Create Spare Channel" on any of the RGB channel.
(You should not use action that colorize the layer in order to do this.)

[ashf]

Or easier way is to create a later that's solid black and invert color of the selection from the spare layer.

[chrisb123]

When I right click on spare channel I dont have a pixel alpha

 

[ashf]

Like I mentioned above, create an empty pixel layer and select it first.
Also see my screenshot.

[chrisb123]

Got it, thanks