Another Great Google Product

From Google we have a new product. Tour the great art galleries of the world at googleartproject.com
Above is a sample of the detail from Rembrandt's Return of the Prodigal Son at The State Hermitage Museum.
Having the luxury of examining great art from the comfort of my home, and in such incredible detail is awesome.
How do you define a great painting? That's tricky business. Too many words, probably enough to fill volumes  are necessary and still there might be differences of opinion.
I wish I was one of those people who can explain why a painting is great to an audience. On the other hand if you look at the brushwork of Rembrandt you don't need any further explanation. His way with paint is just awesome. Sad to think that he died in poverty after an illustrious career.