Colour and Meaning in The Matrix

Green is symbolic of the matrix code. All scenes inside the Matrix have green tint to them. In fact, in the words of the Wachowski brothers, this use of green tint "...was a whole motif inspired by the phosphorous green of old PCs."

Green = sickness, decay, disease, and impending death. Also associated with naivety. All the people inside the matrix don't have a clue that they are really living in a false reality and that they are actually prisoners.

Blue is symbolic of the real world; all the scenes in the real world have a overwhelming bluish cast to them. Many of the objects inside of the matrix are blue also.

Blue = a peaceful, spiritual colour; mentally and physically therapeutic color. It heals, soothes, and relaxes.
When we first see Neo in the real world, he is in poor shape physically and mentally. Morpheus calmly tells Neo to rest and the Neb crew begin to work on his muscles, which have atrophied from being in the matrix pod. These "healing" scenes are filled with blue objects and they have a general blue aspect to them.
Blue is symbolic hope and inspiration. In religious symbolism, it stands for truth as well. When Neo sees Trinity and Morpheus for the first time in the real world, they are surrounded by a misty bluish light. Morpheus tells Trinity that they have "found him." When Trinity questions this by saying, "I hope you are right," he counters with "I don't have to hope."

Dark blue is associated with depression, dejection, and sadness. Cypher has grown very tired of the real world and he is unhappy with the harsh reality of it.

Orange (the colour of the sun and fire) emits a warm, positive feeling and suggests enduring energy, strength, and vitality. Seen in Oracle's kitchen. The Oracle's presence and demeanor reflects these "orange" qualities. She seems to be a warm, positive person who makes you feel at ease.

Orange = drive, ambition, and enthusiasm. Seen in Dojo scene: Morpheus is determined and confident teacher while Neo reveals himself to be a student eager to rise to the challenge.

Red = aggression, anger, danger, sin, and war. Cypher wears a dark red shirt in the real world. It also has a large hole in it where is his heart is located. Also associated with the devil and evil. In this case, the agents are representative of evil as well as Cypher through his alliance with them. Since medieval times, the Devil has been often depicted wearing red clothes or having red skin.

Red is sexuality, passion, lust. The woman in red catches Neo's eye in the agent training program. This is a "red herring ” - something intended to divert attention from the real problem or matter at hand. The whole matrix world is really just one big red herring.
A woman wearing a red coat is there when Neo is taken out of this office building by the agents. She appears to be the only person in that scene who isn't wearing white or black so she stands out.
The colour of blood, red also stands for life, death, and war (the shedding of blood.) Cypher's steak is a blood red. It is during this meal that he makes a decision that will result in the deaths of several people, including his own.
The inside of the matrix pods are red, signifying life/death; primitive.

Black uniforms - powerful, mystery, frightening, uncertainty, aloof, mysterious

White = hope, faith, confidence, and enlightenment. Also purity, innocence, goodness, and perfection.
When Morpheus first plugs Neo into a computer simulation, the screen is totally white and void of anything - represents the loading program having endless possibilities and uses.