Carbon Fiber Polyamide [CF-PA] or Carbon Fiber Nylon is nylon thermoplastic with tiny fragments of carbon fiber mixed in. These fibers can add rigidity and a small amount of strength. Nylon parts should be “conditioned” by being exposed to water for at least a couple hours after printing. This helps normalize the water content of the nylon with the environment which makes the nylon more flexible. Unconditioned nylon is stiffer, making it brittle. It is still unclear, and I am still looking for data, on whether this is the appropriate method for CF-PA, because the introduction of too much moisture may weaken the bond with the carbon fiber. Currently, for CF-PA parts, I leave them in a humid area to normalize the moisture content for several days before using.
Almost all carbon fiber infused filaments are black, this is a limitation of the carbon fiber itself being black.