To paraphrase Putscher's technical description of The Sistine Madonna301: the ground is applied sparingly and only sufficient of it to seal the canvas, to make the colours adhere and not to leave the canvas looking unpainted. A fresco effect is achieved in the aureole around the Madonna by leaving the ground unpainted. The colours are not mixed with white and therefore are so clear that the ground shines through. There appears to be no discrepancy between the ground and the colours. However white is also used as a colour and is applied impasto. This technique, used to this degree, is found only in this one work by Raphael. (The italics are Putscher's.) In a note she cites Hellis :
"It does not in any way resemble, in its technique, any
other by the same master. "302
Wanscher compares the technique to watercolour painting.
Putscher believed that Raphael learnt the 'new' process of
painting thinly on canvas by studying the work of Dürer, who had
sent to Raphael, in c. 1512, a self-portrait
"executed on exceedingly fine linen, which permitted the picture to appear equally on both sides, the lights not produced by the use of whites, but transparent, and the whole painted in watercolours. This work was much admired by Raphael ..."303
and in the Life of Giulio Romano :
"... the likeness of Albert Dürer, drawn from the life on exceedingly fine linen ... This portrait was a very extraordinary work painted in watercolours ... Albert had finished it without the use of any white, having used the white of the linen itself for the high lights ... and being held up to the light it shone through, and was seen on both sides. This portrait, which was held as a most precious possession by Giulio, was shown to me by himself as a kind of miracle ..."304
Putscher states :
"The first picture, that he (Raphael) painted on linen,
is the Donna Velata. It is true, she is not painted with watercolours, but nevertheless with very thin application of colour."305
In Baldassare Castiglione the paint is so thinly applied that the weave of the canvas is clearly visible.