Copied from religionfacts and based on article by Nitin Kumar of Exotic India, used by permission.

Color symbolism is used in a wide variety of fascinating ways in Buddhist art and ritual. In Buddhism, especially in Tibetan Buddhism, each of five colors (pancha-varna) symbolizes a state of mind, a celestial buddha, a part of the body, a part of the mantra word Hum, or a natural element. (Blue and black are sometimes interchangeable.)

It is believed that by meditating on the individual colors, which contain their respective essences and are associated with a particular buddha or bodhisattva, spiritual transformations can be achieved (see the table below).

Following is a table summarizing the meaning of the main color symbols in Buddhism. Click on the color name for a full article and examples of that color. (This article on general color symbolism continues below.)

 
Color
Blue
Black
White
Red
Green
Yellow
General Meanings
coolness, infinity, ascension, purity, healing
primordial darkness, hate
 learning, knowledge, purity, longevity
 life force, preservation, the sacred, blood, fire
 balance, harmony, vigor, youth, action
 rootedness, renunciation, earth
Seen In:
turquoise, lapis lazuli
black thangkas
White Tara, white elephant
coral, red thangkas
Green Tara
 saffron robes of monks
Emotion, Action
killing, anger
killing, hatred
rest and thinking
subjugation and summoning
exorcism
restraining and nourishing
Transforms:
anger into mirror-like wisdom
hate into compassion
delusion of ignorance into wisdom of reality
delusion of attachment into the wisdom of discernment
jealousy into the wisdom of accomplishment
pride into wisdom of sameness
Buddha
Akshobhya
n/a
Vairocana
Amitabha
Amoghasiddhi
Ratna-sambhava
Part of Hum Hum
the dot (drop) on the crescent
n/a
the crescent
syllable 'ha'
vowel 'u'
the head
Body Part
ears
n/a
eyes
tongue
head
nose
Element
air
air
water
fire
n/a
earth

In addition, there is the Buddhist concept of the "rainbow body," the penultimate transitional state of meditation in which matter begins to be transformed into pure light. It is said to be the highest state attainable in the realm of samsara before the "clear light" of Nirvana. As the spectrum contains within itself all possible manifestations of light, and thus of color, the rainbow body signifies the awakening of the inner self to the complete reservoir of terrestrial knowledge that it is possible to access before stepping over the threshold to the state of Nirvana. Understandably, when depicted in the visual arts, due to the profusion of colors, the result is spectacularly unique.

In a spectacular visualization, the Tibetan tradition states that the syllable hum (part of Om Mani Padme Hum), although blue in color, radiates five different colors. The dot (drop) on the crescent should be blue, the crescent is white, the head is yellow, the syllable 'ha' is red and the vowel 'u' is of green color.

The four elements air, fire, water and earth are also identified in the Kalachakra-tantra with four different colors: blue (or black), red, white and yellow, respectively. These four elements are further depicted as semi-circular, triangular, circular, and square respectively. This is a precursor to Tantric imagery where color and geometry (not mutually exclusive) are the basic building blocks making up the whole edifice of Tantric symbolism.

Chakrasambhara-tantra Color symbolism is also of great importance in a mandala, the quintessential symbol of Tibetan Buddhism. The Mahavairochana-Sutra states that a should be painted in five colors: one should start at the interior of the mandala with white and to be followed by red, yellow, blue and black.

The Chakrasambhara-tantra prescribes that the walls of a mandala should be painted in five colors and should maintain the order of black in the interior followed by white, yellow, red and green.

In certain mandalas, the four directions within the palace are indicated by different colors. The east is indicated by white, west by red, north by green and the south by yellow while the center is painted blue.

The Kalachakra-tantra, however, prescribes a different color scheme to indicate different directions: the color black indicates east, yellow west, white north, and red stands for the south. Whatever the color association with directions, the protecting circle of a mandala is almost always drawn in red.