Digital BW, The Print

In my darkroom days, I did some experimenting with very slight split 
toning, like e.g. warm shadows and cool lights, or cool shadows and warm 
lights.

I would like to be able to do that in an archival quality with carbon. 
As I understand, there is no other way than to add other "things" to the 
carbon, right? If I remember well, people started out adding dyes to 
carbon inks, which doesn't sound very archival to me.

Are there other (pigment based?) solutions on the market, that allow to 
preserve those small, but oh so important nuances over the lifetime of 
the print? Can one compose one's own mixes? Can you then control the 
whole thing in PS?

Thanks for your educative suggestions!

Louis de Stoutz