Witches' Sabbath (The Great He-Goat) powdered glass, orpiment and iron oxides. He likely worked with mixed materials. Technical analysis indicates that most of the Black Paintings begun with preparatory drawings. "Witches' Sabbath" is the exception; the final composition seems to have been painted directly onto the wall. Art historian Fred Licht notes that Goya's brushwork appears "clumsy, ponderous, and rough" and lacking finish compared to his earlier work. Licht believes this was a deliberate ploy to physically convey dismay at human inadequacy and his own feelings of personal doubt. Unique in the series, "Witches' Sabbath" was not significantly altered by Goya after his initial work.
James Roberts (painter) was the reason her father agreed to sit for Roberts, that the result was uncharacteristic, and that the book shown was a novel. Roberts was also a scene painter at Blenheim Palace, in 1788 and 1789. In 1789 he was designer for "The Maid of the Oaks", and "False Appearances". a translation by Henry Seymour Conway of "Trompeurs Dehors" by Louis de Boissy. By 1795, Roberts had an appointment as portrait painter to the Duke of Clarence. He exhibited again annually at the Royal Academy from 1795 to 1799. The National Portrait Gallery, London holds 52 portraits by Roberts or