how to use different colors of light for meditation
Various kinds of lights manifest during meditation owing to concentration. In the beginning, a bright white light, the size of a pin's point will appear in the forehead in the Trikuti, the space between the two eyebrows, which corresponds tentatively to the Ajna-Chakra of the astral body.
Blue is the color of the sky, of space. Meditation on the color blue enhances your mental capacity by clearing away the distractions that invade your thoughts. When you close your eyes, it may be easier to visualize violet or indigo than blue. Thus you may want to find something blue to focus on with your eyes open.