Sound, touch, and colour, these are the three qualities of light. Colour is the quality of light, and colour is said to be of various sorts.
शब्दः स्पर्शस्तथा रूपं त्रिगुणं ज्योतिरुच्यते॥ ज्योतिषश्च गुणो रूपं रूपं च बहुधा स्मृतम्।