Luminosity (and other aspects of paintings)
Contemporary British painter, Matt Harvey, describes the painting above by Titian in this way,
This beautiful painting by Titian from the Prado Museum is the reason I wanted to try and learn the technique of painting with a grey layer, or underpainting in grisaille, a technique that Titian pioneered. The flesh appears both taught, as if it was carved out of marble, and fluid at the same time. Titian painted this in Rome, and you can clearly see the influence of Michelangelo in the rendering of the forms and their monumentality. Another interesting fact is that he painted it on Slate. You can see the colour layers as applied over the grisaille and they seem to dance and flicker on the picture plane. It is as if Jesus Christ is illuminated from the inside, and the strokes of glaze glow like flames burning in a furnace. The cloth Christ is wrapped in has an extraordinary quality which maybe I could get to the bottom of by copying.Matt Harvey is not the first nor the last to rave about the transparent and luminous qualities, especially oil paint, when glazes are applied over a grisaille by artists from the Renaissance. Can you see how beautiful and luminous the surface of this painting it? Isn't it fantastic?
What, you can't see it? Ok, you are correct. You can't see squat in this image in terms of the luminous beautiful surface. It is not your fault that you cannot see it. Images online and in books are good, but they are nothing compared to seeing paintings in person. That is why it is an essential part of your education that you go visit museums and see great works in person. You will never fully understand what is possible in paint until you go see the paintings in person.
Think of it this way? Would you ever marry someone based on a photo you saw online? Probably not. Heck you might not even agree to go on a date based just on a photo. Photos are nice, but they have their limits. Go see paintings in person whenever you can!