Some of my favorite colors and some of their effects:
Green :: BALANCE, LOVE, SELF CONTROL
Helps relax muscles, nerves, and thoughts. Cleanses and balances our energy, to give a feeling of renewal, peace and harmony. Green connects us to unconditional love and is used for balancing our whole being.
Blue :: KNOWLEDGE, HEALTH, DECISIVENESS
This is a mentally-relaxing color. Blue has a pacifying effect on the nervous system and brings great relaxation. Ideal for sleep problems. Connects us to holistic thought, and gives us wisdom and clarity enhancing communication and speech.
Indigo :: INTUITION, MYSTICISM, UNDERSTANDING
The indigo energy connects us to our unconscious self, and gives us the experience of being part of the whole universe. Strengthens intuition, imagination, psychic powers.
Brown :: PHYSICAL COMFORT, SIMPLICITY
Brown is friendly and approachable. It is loyal, trustworthy and dependable in a practical and realistic way. In color psychology, brown is honest, genuine and sincere. It relates to the hardworking, the industrious and reliable, with both feet planted firmly on the ground. It is sensual, sensitive and warm, engulfing one in a feeling of calmness and comfort.
So without actually thinking about purchasing or wearing these colors consistently during Reiki work, the universe has chosen for me the necessary colors that will compliment and not hinder a transfer of healing energy.