Here's what I did:
1. Made a new layer and applied the image to it. Burned the sides of the signature to add realistic lighting.
2. Added a black and white gradient map. Set it luminosity at 80%
3. Added the green,orange,purple gradient map. Set it to soft light at 70%.
4. Created a new layer and applied image. Smudged the background a bit.
5. Created a new layer and applied image. Filter>Sharpen>Sharpen. Set at 75%.