Copying colour grades via curves?

[creature]

I'm trying to expand my knowledge of colour grading techniques for photos, and I found this tutorial for a method in Photoshop. It uses Photoshop's curves tool to take a particular look from a source image and apply it to your own picture. Essentially, you build a curves adjustment by sampling colours for a photo's shadows, midtones, and highlights – then set your own photo's shadow/midtone/highlight tone points equivalently. 

Affinity Photo's curves panel doesn't have a colour picker, so this technique isn't directly portable. Can anyone suggest an equivalent? I've used the Gradient Map adjustment layer for something similar, but would love to know if there are other tools that are better-suited or give more control.

[NotMyFault]

Hi,

 

 

Affinity has a color picker in curves, see

 

you can find lots of video tutorials using your preferred search engine, "affinity color grading".

e.g.

Regards,

Timo