This is a Photoshop Tutorial, which you can do in Gimp.
The tutorial is at a beginner's basic level to do, with information kind of on
advanced side. And you may be surprised at what you may learn!
In no way do I claim to have created this effect or take credit for the image used.
You can find this free effect online, posted for Photoshop users.

This is the finished image from the walkthrough that you can learn to do.
I will show you how to do it in a little different way in Gimp. This is more about
informational study than techne. I have included in the Zip file The PDF (Tutorial) and the original
image to work with, so you can give it go, if you're interested.

Didn't look ok until I merged all the layers. My curves were completely different to the tutorial though. I did the same numbers but got lines in different places. Oh I used a public domain photo.

I have these others I posted you can add too,
located in the Gimp tutorials section.

Platinum Old Burgundy FX Effect
Platinum Aqua Smoke FX Effect
Platinum Imperial Purple FX
Platinum Caramel Sugar
Platinum Warm Mahogany FX Effect