Gas chromatography is a very valuable technique commonly used in industries like pharmaceutical production. In art conservation, it is a technique that can expose which binding agents (glue, varnish) were used by the artist, while also providing information on the quantity of the materials used. In this manner, we can better imagine how the artwork was painted. Spectroscopic methods use radiation invisible to the naked eye, like the electromagnetic waves used for X-rays and radio waves used by the radio. The radiation passes through the sample being tested and emits a signal. The signal does not create an image, like in an X-ray, but rather a simple curve on paper. This curve shows the material type and condition of the sample. When applied to works of art, these techniques provide valuable information about the materials used by the artist to create the work.