correct me if i'm wrong, but simple seps isn't meant to create dark films. It is merely an amazing plugin for corel that lets you do color separation, underbases, and halftones, etc. You would still want a rip software to print your films so you can adjust your ink density.
I might be wrong here, but from watching 3-4 tutorials on simple seps I don't see anything that would indicate to me that you are going to get dark output films right out of corel.
I might be wrong here, but from watching 3-4 tutorials on simple seps I don't see anything that would indicate to me that you are going to get dark output films right out of corel.