Hewitt is not without both critics[25] and supporters[26] in his rendering of Cennino Cennini's medieval gesso recipes.[27] Donald Jackson, a British calligrapher, has sourced his gesso recipes from earlier centuries a number of which are not presently in English translation.[28] Graily Hewitt created the patent announcing the award to Prince Philip of the title of Duke of Edinburgh on November 19, 1947, the day before his marriage to Queen Elizabeth.[29]