Using 32bit R G B as alpa masks for CGI Renders

[Morne]

Hi all

 

I can't figure out how to copy just the R or G or B channel from a 32bit image that only contain red green and blue colors.

In photoshop I would just go to channels and select the channel I want for example BLUE (this gives me a pure black and white image, basically an alpha), then I can go to the layers and either paste it as a normal layer, or paste it into a layer adjustments as a mask.

 

Help please!

 

[Morne]

I figured out how. You 1st make a greyscale layer from it. Now I can't figur out how to use that as a mask. Copying the layer and trying to paste it when "editing mask", just pastes a new layer on top, not into the mask

 

I can draw in the mask etc, but not paste anything into it

[paolo.limoncelli]

With the Greyscale layer choose Rasterise to Mask from layer menu, but instead of Greyscale Layer I suggest you to use the Create Mask Layer command.

Move this layer to the side of the one you want to mask (a vertical line appears).

Boom, you're done.

[MEB]

Hi Mome,

Welcome to Affinity Forums :)

Select the image in the Layers panel, go to the Channels panel, then in the second section (the one that doesn't have icons on right), right-click the channel you want and select Create Mask Layer. 

[Morne]

Thanks guys

 

It's a bit strange as its different to what I'm use to, will take some time to get use to it. Easy when you know how. Thanks guys!

[paolo.limoncelli]

Thanks guys

 

It's a bit strange as its different to what I'm use to, will take some time to get use to it. Easy when you know how. Thanks guys!

 

 

Mask/Channels implementation in AP is different from any other software out there and requires a bit of training, but can almost do anything...  :)

[Morne]

I'm on this again...

 

1) How do I use an alpha channel from 1 file, as a mask on another file?

2) If I have a black and white pixel layer, how can I turn it into a mask?

[JQL]

I'm also always trying to do masks my way.

 

I'm used to right-click on them to convert to alpha mask/adjustment layer in Krita.

[James Ritson]

I'm on this again...

 

1) How do I use an alpha channel from 1 file, as a mask on another file?

2) If I have a black and white pixel layer, how can I turn it into a mask?

 

Hi Morne,

 

1) Easiest if you have both files together in one document - so select the pixel layer in one document, copy and paste it into the other document. Then on the Channels panel, right click the layer's alpha channel (it will be named after the layer, eg "Background Alpha") and choose Create Spare Channel.

 

Now select the layer you want to apply the alpha mask to, right click the new Spare Channel and choose "Load to {Name} Alpha" (where {Name} is the layer's name).

 

Sounds more complicated than it is, but it boils down to: create spare channel from source alpha mask, select layer you want to apply it to, right click spare channel and load it to that layer's alpha channel.

 

2) Select the black and white pixel layer, then go to Layer>Rasterise to Mask from the top menu.

 

Hope that helps!

[Morne]

That works fine, thanks James...

 

BUT NOW,

How do I add an adjustment layer to a pixel layer, that already has a mask on it? If I do it, the mask get ingored. Seems instead of adding an adjustment layer to a pixel layer, I have to stick it on top and use the same mask for the adjustment layer than what I did for the pixel layer, seems like double work...

[Morne]

Still not understanding masks in Affinity. Seems way more complex than it needs to be. If anybody has a detailed tutorial, that would be great.

 

In PS I typically have a mask for an adjustment layer, then on top of that have more adjustments and those don't need masks as only the layer below those are affected

Also I often I a mask for a pixel layer, then again a bunch of adjustment layers on top of that that affects only that layer. Can't figure this out in Affinity