Pentimento - pentimiti
An Italian term meaning to repent. "Pentimento" is a condition descriptive of old paintings where lead-containing pigments have become more transparent over time, revealing earlier layers or images. Sometimes the initial drawing by the artist appears or perhaps an earlier painting, which was overpainted. Preventive measures by artists include removing preliminary lines or colors that are darker than the new paint and smoothing out the first layer of impasto before overpainting. Some artists such as Richard Diebenkorn deliberately left "Pentimiti" or traces of pigments from his previous work on that ground as an indicator of human frailty---attempts to create something at an earlier time. Diebenkorn called these leftovers 'crudities', in that they expressed errors or mistakes and were very much a part of the addition and correction processes involved in making art. Source: Ralph Mayer, "A Dictionary of Art Terms and Techniques"