Umbrous

[Quoting Leonardo da Vinci:] Just as there are luminous bodies that emit luminous rays, so there are “umbrous” bodies that emit shadowing rays. An umbrous body is something solid and dense that blocks and creates (casts or projects) shadow, an[…]

... drowned in umbrous shadow.

Indeed, human hope and aspiration has its too-brilliant facet, just as does the self have its too-umbrous shadow: "I don't know if it is reasonable to propose a 'radiant future' to tomorrow's humanity, but we would do well not[…]"

Color in alcohol dark umber, largely uniform, […] Fins all umbrous, or rather dark brown.