The word candid is connected with the word white (implying innocence and freedom from malice). In the context of the etymology of candescence it has more to do with the heat from which it derives than the light it emits. In the literary setting the import is strong emotion and passion. In the artistic milieu it is pronounced gemstone colours.
candescent is glowing with heat; white-hot, while incandescent is emitting light as a result of being heated