Catálogo de publicaciones - libros

The paper presents selected results of EUREKA E!2542 RENOVA LASER project “Laser renovation of monuments and works of art”, realized in the years 2001–2004, aimed at application of laser technique for conservation of artworks and historic objects in architectural scale. Laser technology has been included into a full program of conservation and restoration of Sigismund’s Chapel at Wawel Castle in Cracow, Poland, covering more than 800m2 of decorative, sixteenth century sculptured surfaces.

The paper presents selected results of EUREKA E!2542 RENOVA LASER project “Laser renovation of monuments and works of art”, realized in the years 2001–2004, aimed at application of laser technique for conservation of artworks and historic objects in architectural scale. Laser technology has been included into a full program of conservation and restoration of Sigismund’s Chapel at Wawel Castle in Cracow, Poland, covering more than 800m2 of decorative, sixteenth century sculptured surfaces.

Lasers have been tested, during the recent past, as a useful cleaning method in conservation treatments: this is due to selectivity and precision of its performance. Nevertheless some colour changes have been detected using Nd:YAG laser sources, especially on white and red coloured substrates. Colour changes on white marble and other white architectural materials have already been widely surveyed. This chapter focuses on the interaction of laser radiation with two kinds of red materials: red Verona limestone and terracotta. These materials have been chosen because of their large use in northern Italian architecture and in statuary. Red Verona limestone is not homogenous in hue, owing to the presence of calcareous nodules (lighter in colour) and clay veins (dark reddish colour).

Lasers have been tested, during the recent past, as a useful cleaning method in conservation treatments: this is due to selectivity and precision of its performance. Nevertheless some colour changes have been detected using Nd:YAG laser sources, especially on white and red coloured substrates. Colour changes on white marble and other white architectural materials have already been widely surveyed. This chapter focuses on the interaction of laser radiation with two kinds of red materials: red Verona limestone and terracotta. These materials have been chosen because of their large use in northern Italian architecture and in statuary. Red Verona limestone is not homogenous in hue, owing to the presence of calcareous nodules (lighter in colour) and clay veins (dark reddish colour).

The question as to whether there is a call for laser technology in the restoration of stone artwork is not new. It is to be assumed that restorers and conservators of monuments are already very well informed in this field, as a result of a number of test series by renowned scientists and institutes, the presentation and publication of their findings in specialist magazines and books, several “laser forums” in the past years and the discussion of the method at the sixth LACONA Conference since 1995. There is currently no other technology that has been subject to such critical scrutiny from every angle as laser technology.

The question as to whether there is a call for laser technology in the restoration of stone artwork is not new. It is to be assumed that restorers and conservators of monuments are already very well informed in this field, as a result of a number of test series by renowned scientists and institutes, the presentation and publication of their findings in specialist magazines and books, several “laser forums” in the past years and the discussion of the method at the sixth LACONA Conference since 1995. There is currently no other technology that has been subject to such critical scrutiny from every angle as laser technology.

In order to find out whether the existing laser systems can be employed to remove superimposed layers of paint on secco wall paintings in a selective way, laser tests were carried out on three types of prepared samples simulating three stratigraphies that are frequently encountered in practice. OM, EPMA, colorimetry, μRaman, and FT-IR were used to evaluate the results. It was found that Q-switched Nd:YAG lasers emitting at 1,064nm could be employed to remove unwanted layers of oil paint and limewash, but the treatment of large areas requires implementation of a computer-controlled X–Y–Z station in order to control the parameters. However, the applicability of this technique will remain limited as ablation at the established optimum parameters implied a discoloration of the pigments cinnabar, yellow ochre, and burnt sienna. Moreover, it was observed that no ablation took place when the limewash thickness exceeds 25 μm. Unwanted layers of acrylic could be removed in an efficient way with an excimer laser emitting at 193 nm.

This paper presents results of numerical calculations of graphite (model medium for black encrustation) removal from aluminium (model medium for artwork substrate) using laser ablation method. Theoretical comparison of cleaning rate of graphite as a solid encrustation as well as porous graphite filled with air or water, using pulsed laser radiation, are presented. Moreover, results of numerical modeling of pressure pulse, generated by laser pulse in graphite filled with water, are shown.

This paper presents results of numerical calculations of graphite (model medium for black encrustation) removal from aluminium (model medium for artwork substrate) using laser ablation method. Theoretical comparison of cleaning rate of graphite as a solid encrustation as well as porous graphite filled with air or water, using pulsed laser radiation, are presented. Moreover, results of numerical modeling of pressure pulse, generated by laser pulse in graphite filled with water, are shown.

A low vacuum SEM was used to evaluate the effect of using an Nd:YAG laser as a non-contact technique for cleaning avian eggshells. The technique shows potential, since there are no obvious deleterious effects from cleaning, but further study is required to understand how the laser is interacting with the sample surface.