Greetings!

[Akora]

Here is a tutorial for Gimp that makes a similar result:
http://www.cartographersguild.com/showthread.php?t=594

-Rob A>

Thank you, this is VERY helpful! The only question I have is for the second-to-last step where you say "apply it as a bump map to the original coloured one". How do you do that exactly?

[RobA]

Thank you, this is VERY helpful! The only question I have is for the second-to-last step where you say "apply it as a bump map to the original coloured one". How do you do that exactly?

Select the coloured layer, and Use Filter->Map->Bump map. Then as the Bump Map source (first dropdown) pick the greyscale layer.

-Rob A>