How to get this effect in GIMP:
1.This tut works nicely mainly with blue-ish pictures. Get your base ready, crop, sharpen etc.
2. Duplicate your base and set it to screen.
3. Create a new layer, fill it with bd6a08. Set it to screen
4. Duplicate your base, bring it on top and set it to overlay 80% opacity.
5. Duplicate you base again, bring it on top an set it to overlay.
6. If your picture is too orange after the step no.5, try to erase the screen layer from step no.2, or try to add anoher overlay layer.
Another results: