Methods to know whether the painting fake or not

Spectroscopic techniques

Painted by one of Rembrandt's students

Electromagnetic spectrum

The UV spectrum

Poleye

A hundred years old

IR

Composed of three elemental colors

Yellow

Blue

Green

Pinted during 1839-1906

IR

An underdrawing charocal in it

Short-wave and long-wave UV

Pigements were made in the same studio

The fluorescence data contradict the ultraviolet data