X-rays and art
X-rays are electromagnetic radiations with a wavelength compound between the U.V and the gamma
rays. The employment of x-rays in the field of conservation is precious, due to the fact they are able to
across also opaque body of remarkable thickness. The image which appears on the radiographic plate is
determined by the min or major absorbing of x-rays from the object in exam and especially on the major
opacity to x-rays form certain pigments. In fact pigments having an high atomic weight, like the ones
containing lead or mercury, absorb more x-rays, thus on the plate they result clearer, while organic
pigments and certain mineral pigments(with low atomic weight) appear dark. The radiography of a
painting can furnish different types of information: “the technique used by the painter;? eventually beneath
drafts; ? establish the authenticity of a work; The x-rays exploited in this technique don't exist in nature,
but they are produced by humans using a device called x-ray tube, which is a glass vacuum vial
containing cathode and anode. The cathode, the negative pole, is made by a filament linked with an high
tension circuit. The anode, the positive pole, is placed at the opposite pole of the vial and it made of a
metal and oblique disc. The anode is also called anticathode. The glass x-ray tube is wrapped in a
metallic sheath filled in dielectric oil: the oil both allow to dispel the heat generated by the functioning tube
and guarantee the electrical isolation between anode and cathode external contacts.