Modest Mussorgky's Pictures at an Exhibition is one of the best loved piano suites of all time: its musical imagery seems so vivid and tangible. It has spawned any number of adaptations, ranging from the frequently performed orchestration by Ravel to the 1971s synthesizer-heavy progressive rock version by Emerson, Lake and Palmer. Every performer and arranger of the work superposes their own interpretation of the pictures that Mussorgsky tried to depict in the music.
The Internet being what it is, one can now find renderings of Hartmann's original paintings and sketches that inspired the work. Some of them can be identified fairly reliably; some of them are not much more than guesses on the part of historians. Here's a quick handy guide: it covers all the pictures in the music except the Tuileries, which no-one seems to have any good ideas for. The best site I found most of these from is this Japanese site: there are also several of the pictures on Wikipedia and on the BBC web site.
Plenty of other places to find more, but I couldn't resist getting these together in one place! Enjoy...
11th March 2010