Guillermo Ducker (fl. 1795–1830) was a Dutch miniaturist active mainly in Madrid, Spain between 1795 and 1830. He is known to have painted for Spain's royal family as well as for Madrid's high society, until at least 1813, when he painted a miniature of Joaquina Téllez Girón, Marchioness of Santa Cruz.
Although his first known work is from 1795, the first actual mention of Ducker appears in a 1799 letter from Francisco de Goya to the Secretary of State (prime minister) of Spain, Mariano Luis de Urquijo in which he expressly recommends Ducker and requests Ducker's release from prison in order to paint some miniatures of Carlos IV and his family: "you will have excellent portraits of the Monarchs". His imprisonment may have been due to bad behaviour. Two days later, Ducker was released on condition, as Urquijo noted in the margin of the letter, that he use "the necessary moderation in his language and manners".[1]
Ducker is known to have painted for the royal family, at six ounces of gold per portrait. The Queen of Spain, María Luisa, commissioned copies of portraits of Goya and effigies of the King of Etruria, Louis I and the infantes Francisco y María Isabel.[2]
The Museo del Prado in Madrid has seven miniatures painted by Ducker,[2] including two of members of the Tellez-Girón family and the Museum of Romanticism (Madrid) has three miniature portraits by Ducker, painted between 1800 and 1810.[3]
The Fundación Lázaro Galdiano in Madrid has a miniature Portrait of Josefa Tudó Cathalán Alemani, condesa de Castillofiel, attributed to Ducker, painted around 1805.[4]
The descendants of José Pascual de Zayas y Chacón also have in their possession a miniature of the general painted in 1814.[5]
After having left Madrid for Barcelona, Leandro Fernández de Moratín wrote to a cousin in Madrid in 1817 requesting a portrait, specifying that he would not accept "just any dauber" and that "the most outstanding miniaturist in Madrid when I left was a Dutchman named Ducker; if he is still around, and not blind or paralytic, he could paint really well...".[6]
Ducker's last known work is from 1830.[2]