Among the special qualities of the third period was something Vasari calls grazia, which may be interpreted as grace but incorporates both the idea of gracefulness (as a form beauty), and the idea of divine grace. For Vasari, grazia seems to have been more or less a synonym for a kind of perfect divine beauty.
But what is grazia ? The task of defining and identifying it in a painting is difficult. It may be thought of that which gives a painting a certain air, as something added to beauty but not directly visible. It is a mysterious quality the presence of which makes a painting a great work of art. In the 16, grazia came to be associated with the God-sent inspiration.
A painting or a piece of sculpture came to be seen not as merely the product or creation of a painter or sculptor, but as containing within it some divine inspiration, a spiritual essence emanating from God. The term grazia was used to define this something extra, this special quality of divinely – inspired genius, in a work of art. Indeed, it was the presence of grazia which produced that indefinable perfection in a work of art.
Grazia, however, defied analysis; it was never clear exactly what it was; it was just there in a great work of art. In fact, it came to be referred to in Italy as un non so che (an I-don’t-know-what), which the French in the 17 translated into the phrase je-ne-sais-quoi. A painting may be described as having as certain je-ne-sais-quoi, that something special, which made it a great.