Both Uses of

lurid
in
Harry Potter (#2) and the Chamber of Secrets

The walls were all covered with large, lurid pink flowers.
p. 235.9 *

lurid = surprisingly brightly colored

Lockhart, wearing lurid pink robes to match the decorations, was waving for silence.
p. 236.2

Definitions:

(1) (lurid)
shocking, as from disturbing details of a horrible story, or a color more vivid (bright or deep) than would be expected
(2) (meaning too rare to warrant focus)
meaning too rare to warrant focus:

Long ago, lurid referred to a yellowish color or things and from there to things so shocking they make someone turn pale. Later, but still in the 18th century, it was used to describe a vivid red and is still used to describe vivid colors--especially red.