Colourless
Part of speech: adjective
Definition: Having no, or little colour. water white. Lacking in interest or variety.
Somber
Part of speech: adjective
Definition: Dark or dreary in character; joyless, and grim.Dark, lacking color or brightness.
Example sentence: Every true-crime thing you see goes in with that kind of ominous music and low lighting, so to be able to talk about these things but not have to feel somber about it and not feel guilty that you're not feeling somber about it - I think that's what appeals to me.