Before:
After:
Steps were:
1. Change levels: I dragged the grey and white arrows to about the middle of the little level diagram thing.
2. change to greyscale
3. change to duotone
4. first colour: stayed at default
5. second colour: Pantone 2965C
6. Changed filter to the diagonal strokes
7. played with settings and levels in filter until it looked good.
Pantone 2965C's colour is generally called Prussian Blue. :)