Retouching is among the most sensitive within ethics in conservation since it means to establish the aspect a restored object is expected to have. My opinion is that the looks of an historical object is often as important as its physical-chemical condition, and not intervening provides poor results that might mislead its readability more than a proper intervention. The more we intend to make it as neutral as possible, the least arbitrary, we need to admit that retocuhing requires good taste.