I can hardly describe the discord produced by the comparison of the retouched part of the painting and the part left untouched, the former having lost entirely the immediacy and brio of the brushwork and the latter the mastery of sensitive and discerning touches... For it is true that the more one retouches under the pretext of restoration, the more harm one does, and even the artists themselves, were they able to return, would not able to retouch their painting perfectly on account of the necessary change in the hue of pigments over time... No painting by Titian should be relined, nor any paintings by a number of other painters.... and, even when it is possible, the operation is more likely to result in deterioration than in improvement of the painting.