Feature Request: Paste into channel

[JohnMakesGames]

Hopefully this is a request that is easy enough to understand. In Affinity Photo- If I have a copied layer in my clipboard, I want to be able to paste it into a channel in the Channels tab.

I have a lot of black and white images in different layers and I need to combine them quickly and easily. 

 

[vorple]

I'm trying to de-Adobeify, and being able to do this with CMYK images (and work seriously with CMYK images in general) is one of the last things that I haven't found is doable in other software. 

CMYK image with empty Black channel. Open different Greyscale image, copy, paste into Black channel. In Photoshop this is a simple. Copy, select Black channel so others turn off, paste.

[kirk23]

Paste as a regular layer and add procedural filter where select channel the layer would input  only .

[vorple]

While you sound very skilled and knowledgeable about Affinity tools, and that may be a workable solution, from looking at the interface for procedural texture for a good five minutes, I have zero idea of how I would use it to do that.

Are the options to choose from really: copy-paste-&-just-works, or, learning (I'm guessing) calculus?

[NotMyFault]

There are multiple ways to get the functionality in Photo.

(1) use channels Panel

this requires a few clicks, but works.

• paste layer
• create spare channel from desired color channel
• select destination layer
• click on spare channel to „load to pixel layer K“

(2) use channels mixer adjustment 

we need 2 adjustments layers, one to zero out the black channel in the source layer, and one to zero out CMY channels in destination layer. 

• put channels mixer adjustment above layer you want to paste into
• choose K channel 
• set K slider to zero
• paste layer above
• add channel mixer adjustment, nested to pasted layer
• choose C channel, set slider to zero
• same for M and Y channel
• set blend mode to „add“

Optionally: use merge down or merge visible to flatten the layer structure into one single pixel layer. This is not required, and keeping the layer structure as is allows to simply paste a different layer if you change your mind any time later.

Affinity is encouraging users to use this kind of nondestructive approach. It is a kind of investment initially for learning and setup up those layers, but can provide new opportunities to re-edit parts of your document without undoing, and keeping successor edit steps just in place.

now you get the rendering using the K channel from pasted layer and all other channels from lower layer.

you can save the adjustment layers as presets, or assets so you don’t need to adjust them every time.

Caution: if you have semitransparent areas use method (1), or modify the adjustment layers on top to set alpha channel to 100% offset, and nest it to masking position.

[vorple]

Many thanks, the detailed steps are much appreciated. Glad to see there are ways that it can be done. I'll keep at it.