Hey mate, if you HAVE the PSD of it,
i would go back in PS, and then go, New Layer > image > apply image, then go Image > Adjustments > and then gradient map, then choose the Purple and orangy one.
Then set the layer to Overlay, see if you get any better Depth, then set it to a nice opacity.
Just try it, your out come might be better
Cause i really like the sig, but some more depth in it would be nice.