.. I will endeavour to make clear to men of good will what the word 'material' means with regard to painting and that, without the material substance of paint, a painting is not a work of art but merely a decorative object, or rather, if it deals with an invented painting, the value of the image resides in its spiritual content.
In order to be a work of art, a painting must be very well painted and the good quality of the paint depends completely on the material substance of the paint with which it is executed. This matter, which constitutes the substance of painting, is composed of two elements which are equally important and absolutely inseparable: physical substance and metaphysical substance. These two elements complete each other reciprocally and when they are of a superior quality, create a masterpiece by way of their absolute harmony.