I really like the idea of color for some reason. Green has always been my favorite. Lately I've felt drawn to study physics. In physics light is broken down into various wavelength intensities, each possessing a different vibration or frequency which is translated by our eye and brain into color. Each color has meaning and significance. Physical, emotional, and spiritual.
I sometimes hear the phrase "the color's seemed brighter" or "the color's seemed dim". Usually the first is said by someone who is in love, and the second is someone feeling the loss of love, or a deep disappointment. The phrase also gets used occasionally for someone who has had arrived at a new view of life or new experience heightening the senses. But most commonly colors appearing brighter has to do with love. All of us can probably recall a time when color's did seem brighter.
We know that without light, there is no color. The light from our sun is what gives light to the earth and creates color. Also the light from God is what gives light to our beings. God is light. God is also Love. So when we are "in love" it just may be that we are experiencing a glimpse of the divine light/love and that is why color's appear brighter.