Hmm.. Black? Here is a bit from the website. I know I had or read a guide published by them about the care of the materials. This is just from their FAQ page:
2. How do I care for the leather or King Ranch Embossed Fabric?
Leather Care: The leather we use in our products will last for many years with proper care. In our experience, the best way to preserve leather is to condition the leather every 3 months with King Ranch Leather Conditioner (item#1053). Do not use oil on any of our leather products. Doing so will turn the leather very dark.
King Ranch Embossed Fabric Care: The tan-colored materials we use can be washed with water and any non-abrasive soap. We suggest using soap such as Soft Scrub, which does not leave a film. If the material is marked by a ball point pen, it is important to remove the ink before it dries. The best choice for this is any commercially available ink removing cleaners, but in a situation where such a cleaner is unavailable, hair spray can be used. Spray it on the spot, let it work for 20 to 30 seconds and then wipe it off with a soft cloth. Do not scrub with a lot of pressure or you will dull the surface.