A patent filed with the United States Patent and Trademark Office (USPTO) indicates that Apple is experimenting with a technique to achieve a matte black surface finish on an anodized metal surface.
The patent talks about imparting light absorbing characteristics to the surface of an anodized part that can absorb all the light that strikes the surface to achieve a black appearance.
By the language used in the description of the patent, it is likely that we are talking about a portable electronic device that has internal components that dissipate heat.
Apple notes that conventional techniques used by consumer electronics manufacturers have failed to achieve true black, and the best that has been achieved is a dark gray shade.
Applying a matte black shade to an electronic device like a MacBook or iPhone will also have some benefits. One such use case involves preventing light from reflecting off the camera and using the heat absorbing properties of the matte black surface for thermal management and cooling of the internals.
The matte black finish of an anodized case can provide functional benefits for a variety of form factors, including both smartphones and computers. In any case, it is a patent, which means that we will not necessarily see a MacBook or an iPhone of this color.