How long will oils remain on paper to still be detectable

What type of oil, what type of paper, in what environment is it keep

Body oil,plain white paper,indoor controlled environment

what type of oil, what type of paper, in what enviornment is it keep

Body,plain white ,indoors controlled

Anthropologists in Italy claim they have pieced together Leonardo da Vinci's finger prints from papers he handled. You can not get them by "dusting" but would use various chemical methods to bring them up. Often it is not really oil on the skin as much as salts, fatty acids, proteins and amino acid that transmits the print to paper