Prank or Color Code?

Mozart composed all of his horn concertos for Joseph Leutgeb, a long-standing friend of his family. In Salzburg Leutgeb was in the service of the court ensemble as horn player and violinist before departing for Vienna, where he became known as a performer of Mozart’s horn concertos. In 1786 Mozart wrote his fourth horn concerto in E flat major, which, unfortunately, survives only as an incomplete fragment. For the present new edition in “Breitkopf Urtext,” a reliable early print for the missing sections is used. Nevertheless, this autograph is still a very valuable source, since it contains Mozart’s notation of the work in colored ink! The question as to whether this was one of Mozart’s typical jokes aimed at Leutgeb or whether he had something else in mind, remains inconclusive to this day. Whoever is curious can take a guess as well, since Breitkopf is printing (in its new edition and in autograph form) the sections in color that were originally transmitted as such.