When lights in the room are turned off, the life-sized image of Jesus standing on the shore of the Sea of Galilee fades to a shadow as the white clouds in pale blue sky and green water begin to glow around him, as if all were bathed in moonlight.

Soon the silhouette of Jesus grows threedimensional and appears more like a dark statue than flat image. His robes seem to billow in a breeze. Over his left shoulder the shadow of a cross is distinct to most visitors. Some can see a halo over his head and the bow of a small fishing boat on the shore.

The Catholic Church does not call the 8-foot painting of Jesus miraculous or make any claim about it other than to say it is a phenomenon not perfectly understood. Many assume the painting's effects, which last indefinitely in darkness, result from the painter's skilful technique.

Ault, however, denied that he was responsible for the painting's surreal features. He never duplicated the effects in other works, which were mostly landscapes. "It is said that he was very surprised when he walked into his studio one night and saw the painting glowing in the dark," archivist Corina Santistevan says.

The Shadow of the Cross was the sensation of the 1904 World's Fair in St Louis, Missouri, USA. It was exhibited at the Dore Galleries of London and also shown in other European cities. In 1948, a wealthy Texan, Mrs Herbert Sidney Griffin, bought the painting and donated it to the church in her second, chosen hometown of Rancho de Taos.