John the Baptist was a traveling preacher, a Messianic precursor to Jesus; he is portrayed here in a red robe, fit for a Roman emperor, and holding a staff with a cross on it – foreshadowing Jesus’s ultimate fate. Jesus is garbed in white, just as he is in other depictions of the transfiguration. The figures in the background are witnesses waiting to be baptized, though their countenances remind the viewer of the Holy family of Mary with the young Jesus and John the Baptist. The dove of the Holy Spirit floats above Jesus and the Baptist and the two preachers are similar in appearance (after all, in the Gospel according to Luke, the two were related).
The study is an invaluable treatise on Wolf’s fresco on the exterior, northern facade of the Ljubljana Cathedral, where Wolf restored the faded wall decorations painted by Giulio Quaglio. The techniques Wolf employed were so inappropriate that the restoration itself was all but gone within a century. Only one of Jesus’s arms is coloured in the study, while John the Baptist and other elements (the Holy Spirit, the grass along the water, and John the Baptist’s staff) are unfinished. The composition is that of typical Baroque sacral art (the diagonal from top right to bottom left is accentuated), while the style at the heart of the painting leans on the Renaissance and early Baroque periods.
The National Gallery even holds a sketch of the scene, a true rarity, as the master was wont to destroy his sketches as he went along. It is clear from the identical scene, the grid superimposed on the sketch, and the many holes pocked by a needle that the painter used this very sketch to produce his work.