Laser Cleaning Solutions For Cultural Relic Restoration

There is a growing demand for increasingly high-precision cleaning technologies in the conservation of cultural heritage - technologies that offer greater selectivity while minimizing impact on the original structure of the artwork.

The laser proposes a solution to this requirement, since it provides the operator with a completely new tool that can be integrated with current physical and chemical means. The laser thus meets the growing demand for technological adaptability due to new regulations and the increasing use of lasers by public institutions to protect cultural heritage. Thanks to ongoing research, the range of applications on different materials is becoming wider and wider. The use of lasers on the stone surfaces of individual monuments and historic building surfaces is now established and a widely accepted restoration process.

There are four main advantages to using laser technology to clean the surfaces of historical artifacts and art:
1. Minimize intrusion
There is no physical contact between the laser device and the surface to be treated. This allows work on extremely fragile or easily altered surfaces even before they set. Secondly, by acting directly on the surface, the laser does not require any additional bonding materials or chemical additives.

2. High degree of controllability
The peeling off of the deteriorated layer can be measured as follows - a single pulse only involves a thickness of a few microns, which allows the repair to reach a very high degree of precision.

3. Selectivity
The principle used in laser cleaning is that the different light absorption coefficients of various materials depend on the color of the material. In most cases involving black or very dark colors, the deteriorated layer to be removed completely absorbs light, making the laser removal process almost instantaneous. Vice versa, the substrate of the material to be preserved, which is usually a lighter shade, reflects the incident light to a large extent, thereby limiting or preventing the action of the laser.

4. High accuracy
The cleaning process only involves the area illuminated by the laser beam; the surrounding area is not affected mechanically or thermally. Furthermore, fiber lasers allow processing of surfaces with rather complex structures. The variable focus handheld laser head offers high flexibility of use and can be used to process large surface areas or extremely fine details.