Technically, it has many good challenges including facial portrait, body parts and skin tones, still life with fruit, and fabric with folds! Historically, it also has many mysteries!
This is important in light of David Hockney's book, "Secret Knowledge - Rediscovering the Lost Techniques of the Old Masters". In this book Hockney describes his research that shows that it is highly probable that many artists of this period used optical devices, consisting of mirrors and lenses to assist them in drawing, or tracing, the images that they were to paint.
I recommend the book as a fascinating read! Some people in the art world get upset by this theory. However, I think it just makes sense. At that time artists and opticians were in the same trade unions. Artists made their living turning out paintings and anything that helped their output had to make sense. Artists were in competition and were very secretive about their methodologies, however there is even written documentation about their use of optics.
Hockney makes an empirical observation that suddenly at the time of the invention of optics, paintings of table settings suddenly started to show the wine glasses on the left hand side! The potential result of the use of optics which reverse the image.
Notice that Caravaggio's Bacchus is holding the wine glass with his left hand! Likely the result of the optics that Caravaggio used reversing the actual image. Interestingly enough, there is no evidence that Caravaggio ever made any drawing for his paintings.
Well, I was convinced! So I decided to "Right" my image of Bacchus. So I flipped the image and represent Bacchus offering us the glass of wine with his "right" hand! The following photo depicts an early status of my painting Bacchus Righted. I assume that this depicts the actual motif that Caravaggio was painting from.
Looking back on the painting process, one of the most striking observations is how well the color pool painting technique using Golden OPEN acrylic paints has worked for me. The controlled drying OPEN acrylics have stayed workable on my pallet throughout the ten week period (using the techniques that I detail in the My Painting Methodology section of the website). This has enabled me to reuse the same pools of mixed colors, or add to and modify an existing pool throughout the painting process, simplifying my painting efforts and maintaining color harmony.
I have actually maintained two pallets during the ten week painting process. They are pictured below. You can find every tone or glaze you see in the painting on these two pallets.
I can not over emphasize the benefit of the controlled drying time of the Golden OPEN acrylic paints. When I showed a fellow student, who uses oils, that I have been using the same pools of color for the ten week period, she was amazed and said, "I should switch to acrylics!". Yes, but only OPEN acrylics!