Something about Night Gallery being in color that robs it of coolness. (to me) Weird, hey?
But RSNG's color choices and the cinematography of Lionel Lindon, Gerald Perry Finnerman, et al., brought out a certain realism that looked like the early 70s which was not found on often overlit shows such as Jack Webb series, sitcoms shot on film (The Odd Couple, The Partridge Family, etc.) or flat detective dramas (e.g., Mannix). It made the horror/fantasy seem like it could happen in the real world you lived in.