There's a song that's been with me for the past 10-12 years (song was released in 1975 by record label Reprise), and its lyrics vividly describe various scenes of a historical event in human history. At the same time, I'm an amateur artist/musician in both piano and graphite/charcoal sketching, and over the past year or so I've created a series of artworks that were derived from/directly inspired by the lyrics of this song.
Well, I now have a friend who's interested in purchasing this art ($700 - $1000 USD), and so, I'm wondering if I'd be breaking any copyright law by selling it to him..
For the song, every two to three lines describes a "scene", and I've created a body of work for each scene in the song. Also, the artwork itself is quite consistent with the lyrics. Which is to say that, if you were to see this artwork in a certain order, it'd almost be like "watching the song".
So, ultimately, what I'm asking is..
is copyright law for songs confined to that medium of art? Or, does it also apply across medium types?
I know that if I were to create a movie that's based off a book, and then make profit from the movie, I'd probably be breaking some kind of copyright/IP law.. but, what about going from song to graphite/charcoal art, and for my situation?