Despite its high atomic weight, gold leaf gilding applied to create decorative motifs in countless easel paintings is not usually recorded by X -rays due to its thinness or because of its lack of an underlying layer containing heavy metals. The experimental method developed for this work allowed the observation of the fact that the radiological contrast of the gold doesn't depend just on its relative thickness, but also on other experimental conditions related to the radiological technique that has been used. The 18th century work of art Apacienta mis ovejas , of an anonymous artist from Potosi, is showed as a case study of our experience.