It's very good to see increasing interest in carbon blade shaving. The carbon experience has earned a distinct category in my book. I think in time that more and more wet shavers will come to appreciate these blades.
Treet has a carbon steel blade lineup and I've tried them all. Only one of variant is black though. They are smooth, very comparable to your experience with this blade haul. Just have to be careful about rust though, removing them from the razor after each shave. They last me about 3 days.
first de blades were carbon steel..hek in those days they lasted 1 month of shaves..but you had to use em frequently and keep em dry..as rust would set in..dunno about the new ones