The Mother, the sage Aurobindo’s partner in the teaching of Integral Yoga and founding of Auroville in India, once remarked that “When there is a great darkness inside, you can be certain there is a great light.”
The truth of what may be discovered during a spiritual awakening is that both darkness and light have their unique lessons to reveal. Although you may be expecting a great light, a great unveiling of truth or an explosion into another dimension that is free of the burdens of ordinary life, you are more likely to receive flashes of light, flashes of intuition, and at some point a descent into brief periods of darkness.
An initial activation of kundalini may move upward through the body and as it hits the brain it may brighten and produce multiple colors or pure white stillness. Not that it necessarily will – because everyone experiences this energy in different degrees and has his or her own variety of phenomena. Yoga science suggests the 3rd eye awakening brings forth the light of a thousand moons, and as the crown opens it claims it brings the light of a thousand suns. (The numbers are metaphorical)
Meditation seems to be reorganizing the brain, opening up new potentials, and so often glimpses of light and color spark even before a kundalini arising, in someone who is facing a wall for long periods of time. As energy swirls around various chakra areas there are a variety of colors that may seem dominant, and most images of the chakras show the traditional colors that yogis have associated with each chakra. This may seem important in terms of a person feeling their spiritual progress is moving along, but ultimately to become fascinated by such events leads to a distraction from the full evolving of self-realization. They are passing moments that you do not need to experience, but you might.
If the mind awakens there can be a sense of expansive light, or of floating in space.
This too is not a permanent state, but it can feel like a great releasing of boundaries, so that consciousness no longer feels contained in the apparent form, in the personal body/mind.
And there may be moments, even days of feeling you have been plunged into darkness, the deep darkness described by St. Thomas Aquinas where it is felt that nothing matters and you no longer exist. This can be the mind’s interpretation of a core experience of consciousness.
It is useful to allow the extreme experiences to simply be as they are, to enter them fearlessly, and trust they have something to reveal. It is best not to allow the mind to interpret or create a story around these moments, but to stay aware and curious and trust that these are experiences the psyche is presenting, offering you an opportunity to awaken to the whole of what is, and to release the personal attachment to the perspective the separate self has held.