start with a greyscale(black and white image)
in the drop down menu click duotone
once in duotone, click on the black square, and a colour pallet will show up
click on colour libaries and pick pantone
choose your colours.
for a sepia feel use browns
now that the colours have been picked.
click on the colour boxes
now play with the duotone curve.
make the colours lighter or darker.
now your image is complete, to save it.
Save as> photoshop pdf