The Ebony Clock is a constant reminder of death and symbolizes the inevitability of it. The Masqueraders symbolize all humans and gives creedence to the interpretation that the seven rooms represent the seven ages of man (covered further in the next section).
The revelers could neither stop its pendulum from swinging nor could they prevent its ominous tones from dampering their enthusiasm. Colors play an important role in this story: Red – The most obvious color symbolism in "The Masque of the Red Death" is in its title. The gruesome description of the Red Death gives the color a ghastly connotation, especially in light of the red window panes contained in the death room at the far western end of the imperial suite.
The Red Death symbolizes the inevitability of death.
Although there is no specific disease with the exact symptoms described in the story, critics believe the disease's description has elements of tuberculosis, a disease which killed many of those close to Poe.
Blue/Purple/Green/Orange/White/Violet – These are the colors of the first six rooms in the imperial suite.
I will address them together insomuch that they represent a prism and therefore reflect a progression, lending creedence to the interpretation that the story is an allegory for life.
The third was green throughout, and so were the casements.
The fourth was furnished and lighted with orange-the fifth with white-the sixth with violet.
That at the eastern extremity was hung, for example, in blue-and vividly blue went its windows.
The second chamber was purple in its ornaments and tapestries, and here the panes were purple.