Blend mode to colour?

[Pemican72]

Hey Everyone

http://www.fantasticmaps.com/2015/02/how-to-draw-a-map/ - Jonothan Roberts

I'm trying to follow this terrific guide but get caught at the Lay in the basic colours step.

I can't post pictures but where he goes from brown landscape to green I can, with overlay layers or brushes, only get deeper shadows and I can't find an option to set the blend mode to colour?

He is using PS but he say's you can achieve the same effects in Gimp. 

Can anyone help out? much appreciated for any feedback

Thanks
Nick

[Krikor]

look at https://www.gimp-forum.net/Thread-Blend-...ur-in-Gimp