Violet - Knowledge and Memory, and Black - Death.

Another explanation I ran across to explain the colors are:, Blue means heaven and truth, Purple means sorrow and suffering, Green means nature and hope for eternal life, Orange means strength and endurance, White means light, Violet means dark blood and Black means death or grief.

These are a few of the explanations I ran across in my research.  I hope they help.  As you can see there are many interpretations.

The rooms are blue, purple, green, orange, white, violet, and black, with scarlet panes. The colors are wildly dreamlike and surreal, like entering a state of progressive madness, each color increasingly bizarre. The predominant color, despite all the others competing for attention, however, is red. Red symbolizes blood, and the horrors that are to follow.

The details are in the fourth paragraph, excerpted here:

"That at the eastern extremity was hung, for example, in blue --and vividly blue were its windows. The second chamber was purple in its ornaments and tapestries, and here the panes were purple. 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. The seventh apartment was closely shrouded in black velvet tapestries that hung all over the ceiling and down the walls, falling in heavy folds upon a carpet of the same material and hue. But in this chamber only, the color of the windows failed to correspond with the decorations. The panes here were scarlet --a deep blood color."

The narrator says that the rooms run from east to west, starting with the first room in a vivid blue.  The second room is purple, and the third is green.  The fourth room is orange, the fifth white, and the sixth violet.  The seventh and final room is the only one in which the window panes do not match the tapestries hung on the walls; the room is draped in black, but the windows are blood red.  The rooms run east to west, which is the same direction in which the sun travels, and often the day is considered symbolic of the human lifespan: sunset is representative of birth, the sun is at its height when we are in the prime of our lives, and sunset is representative of death.  It seems, then, that we could read the progression of rooms as the progression through a life, ending in the black and red room of death (with the ebony clock which symbolizes mortality as well).  Given the fact that the people are locked in the abbey, attempting to avoid death, this symbolism seems applicable here.

Further, some scholars believe that the seven rooms parallel the seven ages of man described by Jacques in Shakespeare's As You Like It:

All the world's a stage,
And all the men and women merely players;
They have their exits and their entrances,
And one man in his time plays many parts,
His acts being seven ages. At first the infant,
Mewling and puking in the nurse's arms.
Then, the whining school-boy with his satchel
And shining morning face, creeping like snail
Unwillingly to school. And then the lover,
Sighing like furnace, with a woeful ballad
Made to his mistress' eyebrow. Then, a soldier,
Full of strange oaths, and bearded like the 'pard,
Jealous in honour, sudden, and quick in quarrel,
Seeking the bubble reputation
Even in the cannon's mouth. And then, the justice,
In fair round belly, with a good capon lined,
With eyes severe, and beard of formal cut,
Full of wise saws, and modern instances,
And so he plays his part. The sixth age shifts
Into the lean and slippered pantaloon,
With spectacles on nose and pouch on side,
His youthful hose, well saved, a world too wide
For his shrunk shank, and his big manly voice,
Turning again toward childish treble, pipes
And whistles in his sound. Last scene of all,
That ends this strange eventful history,
Is second childishness and mere oblivion,
Sans teeth, sans eyes, sans taste, sans everything.

Jaques says that men play seven parts during their lives: first the infant, then the school-boy, the lover, the soldier, the judge, then a skinny old man in slippers with droopy tights and glasses, and finally an old man, near death, who becomes like a child again.  Each room corresponds, then, to a different stage of life, again moving from birth to death.

The rooms can have several different meanings, with most being the archetypal symbols of the colors. For example, the blue room can represent tranquility and peace, while the green room can represent envy or life. The way the rooms are arranged is the important point, with the start of the chambers begin in the east, & the end being in the west. This represents the flow of life, & the movement from birth to death. Thus, each room can symbolize a stage of life, or a particular emotion felt at each point.

The one room with definite meaning is the final one. This room, with its scarlet panes seeming to bleed over the ebony tapestries, is clearly the room of death. The clock within represents the ticking of the final moments of life, and the revelers are uncomfortable in the black room, preferring the more "lively" colors. The fact that all the partygoers, and Prince Prospero himself eventually die within that room is not coincidence. It's a not-so-subtle reminder that no one can cheat or escape Death.

There are many speculations as to why the rooms are described in the colors and order that they are. My point of view is that they represent the stages of life. Blue (first) is the color of the unknown and represents birth - the very beginning. Next is Purple - the color of vivacity and life - this is the start of life and knowledge. Green comes third and represents the spring of life - growth. Orange, fourth in line, is the summer and autumn of life - the climax or height of life. Thus begins the decline. White is the winter of life and represents age as we think of white hair and bones. Violet is a shadowy color signifying the end as purple (life) is draped in grey shadows. Black, obviously, would then mean death - but the red window, the only window not in keeping with the monochromatic theme - implies death by the feared Red Death.

The big, ebony and draped Clock that lays "in the last room" represents our battle against time which leads inevitably to death. This was one of Poe's obsessions.

The colors have various meanings according to separate research but they are, thus far

Purple: Royalty, riches

Orange is the flame of the fires of hell or passion of life

Green is substenance on earth, life, reproduction, the cycle of life

Blue is the ascend, the beginning

White is innocence, peace, purity

Violet is know to be attributed to philosophy

Black is death. The end. Despair, obscurity

Remember that the black room also had scarlett panes, so the red of the characteristics of the illness lead to death (both go together).

Check enotes as well for other possible answers given before.

I've seen this question asked somewhat similarly in other ocasions, so it may have been answered.

Edgar Allen Poe was a master at hidden meanings in his works. There have been many discussions and theories of what the colors of the 7 rooms mean. Most of the conclusions all seem to mean the same thing. Prospero wants to keep himself and his friends safe from the red death. He holds a masquerade ball at his castle and welds the doors shut, thinking the red death can't get in. There are 7 rooms and each have a different color.

Most of the theories of these colors are as follows.

Blue represents the color of birth.

Purple suggests the beginnings of growth.

Green represents the color of the spring of someone's life "youth". 

Orange is the color of the summer and autumn of one's life.

White represents the color of age.

Violet is a shadowy color that could represent darkness and death.

Black is obviously death.

The colors represent the stages of human life. The rooms are also arranged from east to west. East is usually the direction associated with beginnings and the west is ending and death. In the story none of the guests ever go into the black room, suggesting that they are afraid of death. When the red death appears, it walks the course of each room. It starts with birth and ends with death. All of the guests, who are so afraid of death, rush to follow it. They themselves end up walking the whole course of rooms, as well. They all start at birth and end up in the black room. In the end, as they all enter the black room, they all die.

The striking of the clock in the seventh room of the castle of Prince Prospero produces a harrowing effect upon the guests as it arrests both the musicians and dancers, and it reminds them of the passage of time. When the clock strikes midnight, the revelers have an even keener awareness of the marking of an end, especially when they become aware of a ghastly masked figure.

After his dominions become decimated by the "Red Death," the supercilious Prince Prospero summons his courtiers to join him at one of his resplendent castles and leave the "external world to take care of itself." Within the castle are clowns, poets, musicians, and ballet dancers to magnificently entertain these guests. Outside resides the "Red Death."

Near the end of six months, the Prince decides to entertain his many guests with a masquerade of great splendor. This masque is to be held in seven rooms of an imperial suite. Each room is situated at angles so that there is no view from one room to the next; also, these rooms are all of different colors and the windows are tinted to match the walls. Only the seventh room, a room shrouded in black velvet tapestries that cover the ceiling and drape down walls onto the black carpet, has windows of a different color: The panes of this room are a deep blood red. This room also has an imposing clock made of ebony that stands against the western wall.

...the brazen lungs of the clock [emit] so peculiar a note and emphasis that at each lapse of an hour, the musicians of the orchestra were constrained to pause momentarily...to hearken to the sound;...thus the waltzers perforce ceased their evolutions; and there was brief disconcert of the whole gay company....

The effect of this clock is so profound that even the giddiest is silent and pale and confused. But, when the tolling of the clock ceases, the revelers resume their laughter, though softer. As the hour strikes each time, the revelers appear more tremulous and disconcerted. Somehow in this room as the clock tolls the final hour, the revelers appear grotesque in the darkness and glare and glitter. It seems as though a "multitude of dreams" stalks the rooms until the presence of a strange masked figure is noticed because his costume has exceeded any decorum: He is "shrouded from head to foot in the habiliments of the grave."

Enraged that such an interloper has entered his castle, the Prince challenges this ghastly figure: "Who dares insult us with this blasphemous mockery?" he calls out as he hurries from the blue room through the other chambers. He holds up a dagger, but before Prospero can use it, he utters a sharp cry. Suddenly, the dagger falls to the floor and, instantly afterwards, so does the body of the dead Prospero. The final hour of life has struck as, one by one, the revelers also die. Nothing of the intruder remains but the wrappings of the grave and the "corpse-like mask."

Edgar Allan Poe's short story "The Masque of the Red Death" is packed full of deep symbolism. It is in the rooms decorated of different colors and the actions of the Prince and his guests. However, one of the most meaningful symbols is the clock. When analyzing the reactions of the guests to this symbol you begin to understand the true meaning of the clocks existence in the story. The revelers reaction consists of immediate arrest of all actions. They stop everything they are doing. The orchestra stops playing and "the waltzers perforce ceased their evolutions; and their was a brief disconcert of the whole gay company; and, while the chimes of the clock yet rang, it was observed that the giddiest grew pale, and the more aged and sedate passed their hands over their brows". This reaction to the clock is due to the what the clock represents. A clock is an instrument of time and these guests have gather essentially in an attempt to hide from the horrifying times they are living in. They are hiding from their own mortality. This clock, when it chimes with its "brazen lungs" reminds them all that they are mortal and that time is still passing. Every time the clock chimes it tells them that they are one hour closer to their eventual demise.

The ebony clock is located in the Black Room and has a pendulum that swings to and from with a dull, heavy, and monotonous tone.  When it strikes the hour, it makes a sound that is clear, loud, and musical, but of such a peculiar,odd sound that the musicians and the whole orchestra pause to listen to it. Because there was no music, the dancers stop dancing, and there is  a brief interruption in the gay partying as everyone listens to the sounds of the clock. It is noticed that the happy or gay revelers grow pale, and the older and more sedate or calm revelers wipe their brow as if they are confused or nervously thinking about something. When the last note of the clock ends, the partying commences, and the band members let out nervous laughs and tell each other that they won't  let it happen again, but it does happen again in 60 minutes.

Time is an important theme in this story. The seven rooms symbolize the seven stages of life. Therefore, this one evening is construed in terms of a life span. As the guests move from room to room, and as the clock signals the passing hours, they move closer and closer to death.

The fact that the clock is "gigantic" illustrates how powerful and unstoppable time is. They cannot stop time and, therefore, they cannot prevent their own deaths. The clock is in the western room. Note the symbolism of the succession of rooms, from east to west, and the path of the sun rising in the east and setting in the west. This all emphasizes the passage of time. This allegorically parallels the life span and the notions of morning/birth and night/death.

When the clock signals the hour, the sound is: 

 . . . so peculiar a note and emphasis that, at each lapse of an hour, the musicians of the orchestra were constrained to pause, momentarily, in their performance, to harken to the sound; and thus the waltzers perforce ceased their evolutions; and there was a brief disconcert of the whole gay company . . . 

Each chiming of the hour interrupts the guests' good feelings. Each chime reminds them of time itself and that each hour, regardless of whether or not the plague might get to them, signals they are one step closer to their own deaths.

At midnight, the clock sounds twelve times. Once again, the music and the dancing stops while the clock sounds the hour. This gives the guests more time (twelve tones) to reflect upon the passage of time. This is the point. Each hour, there is one additional tone. So, each time the hour strikes and the music stops, the guests have increasingly more time to stop and ponder time, life, and death. Symbolically, it is at the twelfth hour that they have the time to notice the masked figure.

The purple room in Poe's The Masque of the Red Death represents the second Deadly Sin, which is Greed. Greed, or avarice, is insatiable, excessive desire for wealth and all material goods.

All seven Deadly Sins are, from first to seventh, Pride, Greed, Envy, Wrath (severe anger), Lust, Gluttony, Sloth. Each has a room assigned and each is present in The Masque of the Red Death. The Seven Deadly Sins are of such a monstrous nature because of the other sins that they lead to.

Poe describes the setting as a "voluptuous scene" with seven rooms, "an imperial suite." This indicates that the rooms must be considered together, thus establishing that if the first room represents the first deadly sin Pride, then the second room represents the second deadly sin Greed, and so on. This idea is given support by the fact that the masked ball was held at the end of the sixth month leading into the seventh month.

Since Greed is the sin of having an insatiable appetite for wealth and all luxuries and goods, it leads to other sins against other people, for instance, people who are left without food or shelter. In The Masque of the Red Death, the second room represents the Prince's magnificent preparations for his self-imposed imprisonment with his courtiers.

His country is "half depopulated" yet he is shut up within the abbey's walls with all manner of riches, beauty, wealth, food and wine. The Greed betokened by this insatiable accumulation of food, wine and luxuries leads to the greater sin of his kingdom's people being left to suffer and struggle alone and without necessities.

Additionally, the purple, or second, room represents the stage of life during which humanity is productive and able to acquire the means of sustaining life. This contrasts greatly with the deprivation of others' lives caused by Greed.

The chimes from the clock send a wave of unease over the guests at the party. When the clock chimes, the musicians stop playing, leaving the chimes to be the only sound throughout the rooms. Poe says that the sounds of the clock make even most carefree people become pale with anxiety; the most reserved people "passed their hand over their brows" out of nervousness.

I do not think much occurs in the black room because the room made the party goers nervous. Any who entered looked so freaked out that there were not many people who wished to actually go into the room. Those who did probably just stood in silence or chatted lightly, as is normal behavior for a party.

It is my understanding that the dreams represent the people at the party in their magnificent costumes, walking around the party, in and out of the various rooms. Poe describes them as freezing where they stand when the clock chimes, just like he describes the guests doing.

The guests are described as being "grotesque," and their costumes were influenced by Prince Prospero and his "guiding taste." They wore clothes with shine and glitter, and the costumes were exciting and strange to look at. Some people wore clothes that did not quite match each other, that were unusual. There is one quote that describes it well:

"There was much of the beautiful, much of the wanton, much of the bizarre, something of the terrible, and not a little of that which might have excited disgust."

In the story, a huge black clock stands against the westernmost wall of the last room in Prince Prospero's hall.  The last room is shrouded in black velvet tapestries, and its window panes are painted red; this is unusual because the windows of all the other rooms are painted the same color as the walls.  However, this last room seems to represent human mortality and death's inevitability as its colors are associated with the mystery of death and blood, it is the final room of the seven rooms and death is our eventual finality, and it is the westernmost room (and the sun sets in the west, as the actual death of day as well as a symbol of death itself).  

Clocks are often symbols of mortality as well, representing the unstoppable passage of time, and the fact that the clock is black (symbolic of death) and that the revelers stay away from the final room and fear the chimes of the clock -- especially when it strikes midnight (the death of day) -- seems to confirm the fact that the clock symbolizes mortality.  Likewise, Prince Prospero's death in this room gives further strength to this interpretation.

The guests of the abbey in "The Masque of the Red Death" are trying to prolong their lives, so time has a heightened significance to them. Outside the nailed up entrances to their new home, owned by Prince Prospero, a plague is raging and killing people swiftly. They have all come to the abbey in order to try to beat it. The prince hopes to keep death away by letting only his privileged guests into this sealed environment.

Yet the guests are always conscious that their time on earth might be short. This is why the loud chiming of the ebony clock in the last of the rooms is so chilling to them. The sound is so loud that the orchestra stops playing, and all the dancers freeze, as if dead or "stiff-frozen" for a few seconds, reminded that their time—their lives—could stop at any moment.

The guests throw themselves into the pleasures arranged by the prince in order to block out the fact that they might not have long to live. In fact, the Red Death does come to the partiers, "like a thief in the night." They all quickly die, and at that point

the life of the ebony clock went out with that of the last of the gay.

The clock symbolizes their lives—when the lives stop, so does the clock.

The allusion to the biblical statement that death comes "like a thief in the night" is a reminder that we are all mortal and that privilege can't save us.

Every time the clock strikes an hour, everyone stops to listen and reflect.

Prince Prospero does not seem to care much about his people.  Rather than take care of them during a time of trouble, he takes care of himself.  His kingdom is besieged by a terrible plague called the Red Death, which kills you within the hour.  He decides to take about a thousand of his closest, richest friends and hide away inside “one of his castellated abbeys.” 

Prospero and his people have walled themselves in well, but Prospero decides to decorate the castle with seven voluptuous rooms.  These are decorated each in their own garish color scheme, with the last “shrouded in black velvet tapestries” with scarlet window panes and a “gigantic clock of ebony.” 

The room, and particularly the clock, clearly creeps everyone out.  They avoid it.  When the clock strikes, something peculiar happens.  The people seem to ponder their mortality.  Musicians stop playing to listen, and the dancers stop dancing.  Everyone stops and listens to the clock.

[There] was a brief disconcert of the whole gay company; and, while the chimes of the clock yet rang, it was observed that the giddiest grew pale, and the more aged and sedate passed their hands over their brows as if in confused reverie or meditation.

 The clock seems to remind them that while they may be safe and sound within, there is death and pestilence without.  How much longer can they remain in their cocoon?  How safe are they really?  Has Prospero’s charade really worked?  Have they really cheated Death?

 The answer comes in the fifth or sixth month of their seclusion at midnight, when an uninvited guest arrives at the party.  The “mummer” seems to be in the costume of the Red Death.  The guests deem this in bad taste, but Prospero is incensed with anger.  He tries to attack the "man," running through all seven rooms and stopping in the one with the clock. 

And one by one dropped the revellers in the blood-bedewed halls of their revel, and died each in the despairing posture of his fall. And the life of the ebony clock went out with that of the last of the gay.

As the clock strikes its last, they are all dead—including Prospero.  The clock, of course, is symbolic.  It is death.  The people were reflecting on their own mortality, seeming to know every time the spooky clock struck that they were going to die soon.

Death was not invited to the party, but he arrived anyway.  Prospero’s fantasy that he could shut himself away and create a world where he could escape death was unrealistic.  One way to look at the seven rooms is as the stages of a person’s life.  The last one is death.  This is why Prospero runs through them, and also why they have windows for the sun to rise and set through, with the last one having red panes.  Prospero believed that he could cheat death even in creating this elaborate mimicry of the passage of life, but he was wrong.

The rooms in Poe's "The Masque of the Red Death" symbolize the progress of life from birth to death. The first evidence of this lies in the alignment of the rooms themselves. Poe explicitly states that they move from east to west, referencing the movement of the sun from dawn to dusk. This serves as an extended metaphor for human life. The first room, blue, lies at the abbey's easternmost wall. We can take it to symbolize birth, the start of life, the dawn. Meanwhile, the final room, at the west, is black. It symbolizes death, the end of life, the dusk. The other rooms represent bright, happy colors up until the next to last room, violet. This color seems to hint at the setting of the sun.

It also worth noting that a clock rests at the western wall. Everyone in the abbey already fears this room, and when the clock chimes the hour, "there was a brief disconcert of the whole gay company." The clock represents the inevitability of death, the very thing Prospero and his retinue are trying to avoid. Further, the windows in this final room are "blood-tinted panes," and the light gives everyone who enters the chamber the impression of having a blood-streaked face. The title of this story alone reveals how closely Poe associates the color red with death.

Finally, when the Red Death does come, it begins in the blue room, and Prospero and the others pursue it through all the chambers until they reach the black one. Even in life, even in birth, the specter of death is present. The rooms in the abbey represent the passage of life, from birth to death, and the inescapable fear of that eventuality that no living being can escape. 

It is key to realise that each of the seven chambers and the way that they are positioned running from east to west, to correspond with the rising and setting of the sun, allegorically suggests the different stages of man's life as he is born and starts his inexorable trek towards death. Let us consider how the final seventh chamber is described so we can establish its allegorical significance:

The seventh apartment was closely shrouded in black velvet tapestries that hung all over the ceiling and down the walls, falling in heavy folds upon a carpet of the same material and hue. But in this chamber only, the colour of the windows failed to correspond with the decorations. The panes here were scarlet--a deep blood colour.

Also important to consider when trying to work out the allegorical significance of this room is what happens here. Let us remember that the guest disguised as the Red Death walks through all of teh chambers before finally confronting the enraged Prince Prospero in this seventh chamber, where the arrival of the Red Death is discovered and greeted with intense dismay. The combination of the black of the trappings of this room and the red of the windows strongly points us towards this seventh room allegorically representing death, and death at the hands of the Red Death.

The clock in Poe's story is a symbol of death, reminding the party goers that their time is short.

The people in the castle are there trying to escape the "red death," a disease which sounds ominously like the Black Death or bubonic plague that wiped out a good portion of Europe's population in the 1300s and beyond.

The guests are partying, trying to enjoy life and forget the troubles surrounding them, when the clock chimes the hour with "brazen lungs." The sound is so loud and peculiar that it stops the orchestra from playing. People stop dancing and grow nervous and pale at this reminder of the passage of time and their own mortality. People pass their hands over their brows—everyone is briefly disconcerted until the chiming ends. Then the party resumes.

Poe devotes a whole paragraph to the chiming of the clock to demonstrate that even in this supposed sanctuary, the privileged few cannot escape the specter of death.

In "The Masque of the Red Death," the clock is extremely important as a symbol.  The timepiece represents time itself as it relates to the members of the group locked away in apparent safety.  The members of the group dance and party while those outside the gates of the castle are dying of the "red death."  Those within the castle walls do not realize that their time is nearly over, as well, which is what the clock symbolizes.  When the clock stops, it means that their time is over, as well.

The ebony clock in Poe's classic short story symbolically represents mortality and the transient nature of human life, which Prince Prospero and his revelers desperately attempt to prolong while celebrating in his castellated abbey. The ominous ebony clock is located in the seventh room, which is the most western chamber of the prince's imperial suite. The location of the clock is significant and corresponds to its symbolic relevance. The western orientation of the room corresponds to the sun setting in the west, which symbolically represents death in accordance with the interpretation of the sun's path. The fact that it is located in the seventh chamber also corresponds to death and is fittingly the room where everyone dies once the Red Death personified enters the imperial suite. The ebony clock's association with mortality, the transience of human life, and death is suggested by the revelers' reaction to the sound of its bells ringing every hour. Poe writes,

...it was observed that the giddiest grew pale, and the more aged and sedate passed their hands over their brows as if in confused reverie or meditation. (2)

This "disconcert and tremulousness" indicates that the guests are reminded of their own mortality by recognizing that their time on earth is quickly passing whenever they hear the sound of the clock striking. After the Red Death personified enters the suite, Prince Prospero and all of his guests die in the seventh chamber as the ebony clock strikes twelve. The symbolic nature of the ebony clock is once again emphasized when Poe writes,

And the life of the ebony clock went out with that of the last of the gay. (5)

We know that the clock was located in the red room, and that its clang was neverending. It was imposing, and it could be seen by everyone. This is a grim reminder that time goes on, and our minutes keep passing by.

It was in this apartment, also, that there stood against ... the western wall, a gigantic clock of ebony. Its pendulum swung to and fro with a dull, heavy, monotonous clang…

We also can determine from the depiction of the clock is that its ebony color reminds us of a funeral, as if the clock was ready for one since, after all, the way Poe breaks down time not as a collective abstract, but breaks it down into seconds, which run out quicker, is the manner in which it is telling us how brief life also is.

…and then, after the lapse of sixty minutes, (which embrace ... three thousand and six hundred seconds of the Time that flies,) there came yet another chiming of the clock

A good example of symbolism in "The Masque of the Red Death" is the imperial suite in which Prince Prospero and his guest hold their party. Instead of being a long corridor of rooms, connected by doors so that the entire length can be made visible, the suite is formed of rooms that connect around sharp corners, and each room is styled with a different color:

To the right and left, in the middle of each wall, a tall and narrow Gothic window looked out upon a closed corridor which pursued the windings of the suite. These windows were of stained glass whose color varied in accordance with the prevailing hue of the decorations of the chamber into which it opened.
(Poe, "The Masque of the Red Death," xroads.viginia.edu)

Because of the prevailing theme of impending and inevitable death, the rooms symbolize various stages of the human life. Each room is colored differently, because each part of a human life is different; the rooms cannot be seen from one another, because the future is hidden and the past cannot be changed. As the Masque itself passes through each of the rooms, it is unhindered; the last room, where the Masque is revealed, is black with red glass, the colors of death and the plague itself. As each guest dies in their respective room, the random and senseless nature of death is seen; people often die in childhood, or in accidents, and so the rooms represent both the length and finite nature of life, and the pain of dying before one's time.

The hourly chiming of the big, black clock makes Prince Prospero's guests extremely nervous, to say the least. Each chime acts as an uncomfortable reminder to the assembled throng that they are all one hour closer to their deaths.

The revelers at Prospero's party had hoped that they could put all thoughts of death out of their minds and enjoy themselves. But the insistent chiming of the clock spoils their fun. To make things just that little bit creepier and more unnerving, the musicians stop playing whenever the clock strikes and so everyone finds it impossible to avoid hearing the chimes. Even the most carefree of party animals turns pale with anxiety on being reminded of their inevitable fate.

Prospero and his guests thought they could leave their sense of mortality at the door of the castellated abby. But the clock is there to remind them that they cannot, no matter how hard they try.

In one sense, the only room color relevant to the plot of the story is the black room with the red window.  In most Western cultures, black, partly because it represents night when humans are most vulnerable, is the color of death and dying, sadness, evil, fear, unhappiness, and anger.  If someone says, for example, "I'm in a really black mood," you do not want to be near that person.  In the context of "The Masque of the Red Death," the fact that the window is red is especially ominous because red often symbolizes blood, so the combination of a black room with a window that transforms all light into a red glow carries nothing but negative connotations.

For the other rooms, the colors are less meaningful to the story but add to the overall Gothic effect: blue is often associated with life because it is the color of water; purple, royalty and wisdom; green, nature, youth, but also jealousy ("the green-eyed monster"); orange, energy and enthusiasm;white, purity, spirituality; violet, beauty and passion.

Poe tells us that the layout of the main hall is very different from a typical castle's large, open hall.  Instead, the Duke, to suit his "bizarre" tastes, has divided the area into smaller rooms with a

sharp turn at every twenty or thirty yards, and at each turn a novel effect. To the right and left, in the middle of each wall, a tall and narrow Gothic window looked out upon a closed corridor which pursued the windings of the suite.

We don't know exactly whether these rooms create an overall pattern, but what is important is that they seem to be designed to keep people in rather than out, as in "trapped," and the rooms add to the overall Gotic effect of the castle's interior, particularly because they are not well lit, and the colored windows enhance the surrealistic atmosphere.

An important element in the plot is that the Red Death makes its way through all the rooms, thereby infecting all the revelers in each room, and ends his walk in the black room with the red window, the Red Death's symbolic home because the room itself mirrors the effects of the disease.  In fact there is no other room in which he could have logically ended his visit to the Prince's castle.

In his short story The Masque of the Red Death, Edgar Allan Poe devotes considerable time to physical descriptions of Prince Prospero’s abbey, specifically, the adornments of the seven rooms that collectively comprised “the imperial suite.” Each of the seven rooms features a different color. It is the seventh room, decorated in black with windows the glass of which were “scarlet—a deep blood color”—that contains an imposing clock, described by Poe’s omniscient narrator as “a gigantic clock of ebony” with a pendulum that swings, as the narrator notes:

“. . .to and fro with a dull, heavy monotonous clang . . . a sound which was clear and loud and deep and exceedingly musical, but of so peculiar a note and emphasis that at each lapse of an hour, the musicians of the orchestra were constrained to pause, momentarily, in their performance, to hearken to the sound; and thus the waltzers perforce ceased their evolutions; and there was a brief disconcert of the whole gay company; and, while the chimes of the clock yet rang, it was observed that the giddiest grew pale, and the more aged and sedate passed their hands over their brows as if in confused revery or meditation.”

Prince Prospero’s clock plays a prominent role in the progression of Poe’s story. The swinging pendulum, reminiscent of the giant pendulum from his short story The Pit and the Pendulum, represents an ever-foreboding presence amidst the merriment that defined the prince and his friends’ carefree demeanor. While the music plays and the partyers dance and the magicians and “fools” entertain the assembled elite of this fictional society, the gaiety is interrupted every hour by the clock’s ominous chimes, each occasion immediately followed by a resumption of the merriment.

It is the clock’s chiming that, at the stroke of midnight, signals the story’s most prominent and irreversible shift from its emphasis on partying to an atmosphere of impending doom. Once again, as Poe’s narrator describes the scene:

“ . . .now there were twelve strokes to be sounded by the bell of the clock; and thus it happened, perhaps, that more of thought crept, with more of time, into the meditations of the thoughtful among those who revelled. And thus too, it happened, perhaps, that before the last echoes of the last chime had utterly sunk into silence, there were many individuals in the crowd who had found leisure to become aware of the presence of a masked figure which had arrested the attention of no single individual before.”

The chiming of the clock, as it had regularly, every hour on the hour, causes a momentary lapse in the debauchery and gaiety that has stood in stark contrast to the wide-spread misery occurring outside the castle walls. This time, however, it is different; this time, the ominous tone that has descended upon the partyers with the clock’s chiming is different. It is accompanied by the realization that a masked  intruder walks among the gathered throngs and that this interloper represents a threat to the tranquility and security the revelers had enjoyed. In short, the chimes affect the guests by interrupting their fun and replacing the light-hearted atmosphere that otherwise prevailed with an ominous sense of foreboding.

The gigantic ebony clock on the western wall of the seventh chamber symbolically represents the inevitability of death and serves as a constant reminder to the revelers that they have a limited time on earth. The clock is specifically located in the dark, blood-red seventh chamber, which symbolically represents death. With each heavy, monotonous clang, the revelers shudder in fear, stop dancing, and are reminded of their mortality. The ominous chimes damper the mood of the party, and the ticking clock represents the transient nature of life.

As Prince Prospero and his guests attempt to outwit Death by secluding themselves inside the abbey, the ebony clock continually reminds them that they will eventually meet their demise. At the end of the story, the personification of the Red Death arrives at the stroke of midnight and Prince Prospero dies in front of the foreboding ebony clock.

In Poe's classic short story "The Masque of the Red Death," Prince Prospero invites a thousand of his aristocratic friends to seclude themselves inside his castellated abbey while a deadly pestilence known as the Red Death wreaks havoc on the surrounding countryside. During the fifth or sixth month of their seclusion, Prince Prospero holds a bizarre masquerade in his seven-room imperial suite to entertain his guests. Each of the seven rooms of Prince Prospero's imperial suite is decorated in a different color, and the rooms span from the eastern side of the abbey to the western side. The color and location of the rooms are symbolically significant and represent the seven different stages of human life.

The most eastern room is colored blue, representing birth and the beginning of life. The next room is purple, which symbolizes growth and maturation. The third chamber is green, representing youth and adolescence while the fourth chamber is colored orange, which symbolizes the summer or autumn of life. The fifth chamber is white, representing old age and the sixth chamber is violet, which symbolizes illness and disease. The seventh and most western chamber is shrouded in black with scarlet window panes, resembling a deep blood color. The seventh chamber symbolically represents death, and the ebony clock inside the room serves as a reminder of the transience of life.

In Poe's classic short story "The Masque of the Red Death," Prince Prospero holds an elaborate, eccentric masquerade in his imperial suite and instructs his guests to dress in bizarre costumes. There are seven rooms in Prospero's imperial suite and each room is decorated a different color.

The seven rooms and their colors allegorically represent the seven stages of life. The easternmost room is blue and represents birth while the second room is purple, symbolizing growth. The third room is green, representing youth, while the fourth room is orange, symbolizing the autumn of life. The fifth room is colored white, representing old age, and the sixth room is violet, which represents diminishing health.

The seventh and final chamber of the imperial suite is black with scarlet panes that resemble blood. The final chamber is also located at the western side of the suite and symbolically represents death. It is in this chamber where the large ebony clock stands, reminding the guests of their mortality as each hour passes.

Among each of the chambers, the masqueraders dance, indulge in alcohol, and enjoy the bizarre, grotesque nature of the party. Poe refers to the revelers as "dreams," and they proceed to move through each room as they enjoy the eccentric, exciting atmosphere. The only chamber the masqueraders purposely avoid is the ominous seventh room. Toward the end of the story, the personification of the Red Death enters the masquerade, killing Prince Prospero and all his guests in the seventh chamber.

Poe impressed upon the reader the significance of the clock by waiting until the end to speak about it and the effect it had on the guests at the party in detail. He describes the colorful rooms rather briefly, basically just saying that they were furnished, decorated, and lighted in whatever color it happened to be, but then he reaches the black room. He recounts that the black room was covered in black velvet, but the stained glass windows through which the light of the tripod shone was blood red rather than matching the rest of the room. Then he describes the feeling that came upon people when they stood in the room, following that with a long paragraph about the effect that the chimes of the clock had upon the entire party. The attention he shows to the clock in relation to the rest of the description of the party proves the importance of the clock to the story.

Many scholars believe that the seven rooms in Prince Prospero's castle refer to a speech made by a character named Jacques, from Shakespeare's As You Like It.  In this speech, Jacques addresses what he calls the "seven ages" of a person's life, the seven parts or roles that he plays:

All the world's a stage,
And all the men and women merely players;
They have their exits and their entrances,
And one man in his time plays many parts,
His acts being seven ages.  (2.7.139-143)

The interpretation of the rooms as symbolic of a person's path from infancy to death, ending with a black clock -- both the color and the object often associated with mortality and death's inevitability as our time ticks away -- is reinforced by the way the rooms are situated, from east to west.  The sun rises in the east, the birth of day (often symbolic of birth in general), and sets in the west, the death of day (often symbolic of death in general).

In this scheme, the blue room represents the unknown from which we come, as infants.  Purple, then, the second room, combines blue (unknown) and red (which symbolizes life and intensity), signifying the beginning of our growth.  The green room, third, represents youth and vitality, as green so often does.  Orange, the fourth room, represents the summer and fall of life (our prime and early decline.  White, then, the fifth room, is old age (as our hair grows white with age).  Violet, in the sixth room, combines blue and purple, suggesting shadow and decline, even a return to the unknown from which we came.  Finally, the seventh room of black and red symbolizes death, and this is why the revelers stay out of that room and dread the chimes of the clock, especially at midnight (the death of day); they fear death.  

The setting in this story is incredibly important. It involves the seven rooms all of different hues, but also the clock. The clock itself is a symbol in this story and points to one of its major themes. To understand symbolism you must look at how the object is used by the author. In this case, we examine the characters' reaction to the clock.

Remember that the characters are hiding from the pestilence of the "Red Death". "No pestilence had been so fatal, or so hideous." In a sense, they were hiding from death and mortality. The characters react to the clock by stopping everything they are doing. The orchestra stops playing and "the waltzers perforce ceased their evolutions . . . it was observed that the giddiest grew pale". This is because the clock is an instrument of time and thus symbolizes mortality. The characters hear the chimes of this clock and are reminded of how, no matter where they hide, they will all eventually die.

Your original question had to be edited down so that it only asked one question, according to enotes regulations. I have chosen therefore to focus on the way the setting operates symbolically in this story. It is clear that this is a richly symbolic tale, and therefore the meaning is closely linked to Poe's use of symbolism.

Let us remember that there are seven rooms, each of a different colour. Seven is a key number that suggests the cycle of life and time passing. For example, we have seven days in a week, and then we have the seven stages of man. Let us also remember that the colour of the seventh room, black, is richly symbolic of death, and likewise we need to recall that it is in this seventh room that the clock (which again symbolises time passing) is housed. Of course, Prospero and his guests have locked themselves away in an attempt to stop the inevitable - to halt the ravages of time of live for eternity. The intruder, who could be said to symbolise death, shows that this is impossible. It is strongly symbolic that as Prospero follows the intruder through the other rooms to the seventh, he is, unknowingly, walking to his death, as he meets the intruder at the final stage of life and dies there.

In this tale, therefore, Poe uses the setting symbolically to convey his message of the impossibility of outwitting or running away from death - we are all subject to the passing of time and our own mortality, something that Prospero and his fellow revellers tried to ignore up until the last minute.