pure dye. Later,"Pope Paul II in 1464 introduced the so-called 'Cardinal's Purple,'" which was extracted from an insect. (Podhajny, par. 10).Purple is also associated with spirituality and mystery. Another way to think about purple is that it is the combination of hot red and cool blue.Red is often associated with blood, and thus with life, but also with death (the pouring out of blood). It is a warm color (warm or hot blood), but also a color of autumn.Orange: also a warm color, and a color of autumn. Both colors of autumn can be thought of as foreshadowing the end of life (the leaves turn red and orange in autum because they are dead or dying).White: for Western civilizations, represents cold and death. Black is, as you said, associated with death, but it also associated with the unknown, and often with fear (most of us have a fear of the dark when we were young). Black hides things - it is a color of blindness.Reference: Podhajny, Richard M.,Ph.D. "History, Shellfish, Royalty, and the Color Purple." Paper, Film & Foil Converter. 1 July 2002. 13 November 2007. <http://pffc-online.com/mag/paper_history_shellfish_royalty/>

Red refers to death, having a connection to blood, the life force of humanity.  Symbolically, green represents growth, as is connected to vegitation and spring.  Purple, a color of royalty, represents achievement is society.  Orange refers to the autumn of life, or middle age, while white refers to old age (as in white hair).

I researched this question online and came up with a couple of answers that I feel could be relevant to your question. The seven rooms might signify the 7 stages that a person goes through in their life: birth, toddler, childhood, teen years, middle years, senior years and death.

In the story the placement of the rooms is also significant to this theory.  The rooms go from east to west which represents the way the sun rises, or is "born" each day and then sets or "dies" each day.

It has also been said that the seven rooms represent the seven deadly sins: sloth, lust, gluttony, avarice, pride, anger and covetousness.  The Prince definitely displays all of these sins throughout the course of the evening.

The colors also signify the following  Blue – Birth, Purple - Royalty, Power, Green - Growth and Life, Orange - Destruction or Fire, White – Purity, 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.

Some readers have proposed that there is a link between the order and colors associated with Prince Prospero's rooms and a famous speech from William Shakespeare's play As You Like It. The character Jaques says,

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.

Jaques claims that the whole world is like a stage, and that people are simply playing their assigned roles on that stage. A man, he says, plays seven different parts during his lifetime, and each of these might correspond to a particular room.

The blue room, then, represents the infant, the "unknown" from which we come when we are born. The purple room combines blue (birth) and red (life and passion and intensity), suggesting the beginning of growth. The green room represents our beautiful youths and early adulthood. The orange room would signify the colorful summer and fall of life—our prime through the end of our middle age. The white room could refer to old age (when our hair turns white). The violet room combines blue and purple, suggesting a return to the unknown, in shadow and decline. The black/red room signifies death, and this is why the revelers steer clear of it. They fear death, which is doubly signified by the black clock in the room.

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.

Several scholars have given a diversity of meanings to this question, but one of the most accepted ones is that the seven colors represent stages of insanity. Some others say they represent stages of life until the Prince reaches the last room, which is when he ultimately died. But for sure, as u see the progression of Prince Prospero from room to room, you realize that he is getting increasingly uneasy, and is about to lose his mind. The colors are blue, purple, green, orange, white, violet, and black (the color of mourning, and 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.