The Solarisation or Sabattier effect is one of the earliest known photographic effect. You can read about it in Wikipedia (http://en.wikipedia.org/wiki/Solarisation). Of course this effects can be created in Photoshop using NIK Color Efix or Silver Efix plug-ins. Of course you can create this effect also directly in Photoshop directly (http://photo.tutsplus.com/tutorials/post-processing/quick-tip-using-adobe-photoshop-to-create-a-solarised-photograph/). Keep in mind, not every image is suited for this effect! So here is the exercise for the week: Create images with the help of the Solarisation effect.
I found that the reflection in this instrument in contrast to the arm of the player is quite interesting. As always, enjoy this exercise!