Alpha channel is driving me crazy, how is it done in Affinity?

[hl24a3]

Look at the layer and channel panels on the attached image for details, but basically when I export this image it always exports a combined alpha of all layers and I want the alpha of Sylvester only to be exported, how do I do it in Affinity?

 

 

 

[HVDB Photography]

Document > Transparent background

Uncheck all the other layers

Export "Sylvester" as a PNG-file

[hl24a3]

I know that, but the question is how do I lets say have a map and in alpha a continent outline without removing through transparency the water, in Photoshop it was easy you could dump into alpha whatever you wanted in affinity alpha is automatic so to say I couldn't find a way to be able to manualy insert in shape there

[R C-R]

Hi, ds24a3!

 

If I understand what you are asking about correctly, you want to export the alpha channel of a single pixel layer to a separate file. If so, I assume you want a bitmap (raster) image file, probably a greyscale representation of the transparency of the layer, similar to what you get when you use a mask & right click on it to select the Edit Mask option.

 

To do that, I believe all you need to do is select the layer in the Layer panel, & in the Channels panel, right click on the alpha channel for that layer (not the Composite Alpha channel item above it) & select Create Greyscale Layer from the popup menu. Then export that layer only to a new PNG. In the "More" section of he Export dialog, you may wish to change the Pixel Format to Grayscale 8-bit or Grayscale 16-bit.

[hl24a3]

I know what you are talking about, this is to make a separate file with gray scale alpha not what I want.

 

I'll show you on example I found on google, look below, this is from Photoshop, in there it is possible to have normal RGB channels plus ALPHA which can contain any black and white shape and when you save that file it is not transparent you still see the background like normal plus you have the alpha to be used in other apps like Fusion or 3dsmax or whatever.

 

In affinity when I do mask it creates composite alpha but then everything black on alpha gets transparent in the file and there is no way to use color channels as normal texture and separately alpha as cutout for other purpose.