The resulting ekphrasis has to add to the experience of the original art work, help vivify it or express its essence through the skillful use of language. Ekphrastic writing tends to be hyperbolic and enthusiastic, rather than understated, but that is only a tradition. For some examples of ekphrastic writing, see John Mullan's compilation in The Guardian of important ekphrastic writing.
Here is a paragraph of ekphrastic writing I wrote based on a little painting I have in my room.
Her small face stares intensely out at my world and asks for my opinion. On what? On her world or the outside world? Her world is a small square of wood with infinite depth. Bluegreen fog, white flowers opening their erratic petals, pink spheres, paler pink flowers that may be birds, a red table top that may be a brick path leading to somewhere inaccessible to this world. Perhaps to hers, even. Someone has instructed her to wear a blue sundress. A sheaf of long orange hair sweeps over her shoulder and lies down the front of her chest. She is bent forwards, perhaps to get a better look out of the square window of glass that lets her see out into this world. She smiles as though she knows what I might say. I dare you, she says.
