Well, this is a little trick to have a perfect "Sepia tone" in your photos in 2 step.
Open a photo, I've used one of Natalie (you like her?).
Now go on "Image - Adjustment - Desaturate".
Then on "Image - Adjustment - Color balance" and set:
Shadows: +25 0 +50
Midtones: +65 0 -75
Highlights: -10 0 -100
Done, your sepia tone it's ready:
