Final answer:
The two great lights that get special mention are natural light and candle light, which were the only ways things were illuminated for most of human history.
Step-by-step explanation:
The two great lights that are being mentioned in this context are natural light and candle light. The discussion is about the importance of vibrant and colorful light in making an impression. It is mentioned that electric lights did not exist for most of human history, so natural and candle light were the only ways things were illuminated.