IMPROVING MEASUREMENTS’ SPATIAL PRECISION BY MEANS OF 3D PRINTERS-BASED SYSTEMS. A CASE STUDY: COLORIMETRIC ASSESSMENT OF MODERNIST HYDRAULIC TILES

Abstract. The ability to repeat analyses on the same very small area of a surface is crucial to obtain reliable comparative data. For example, in a painting the boundary between two different, small painted areas can be very blurred; if an analyst needs to track over the time a specific and tiny pigment spot (e.g., to assess the reliability of a conservation treatment), manual positioning of the analyser can lead to a mismatch that might undermine any data comparison. The use of automatic positioning systems can improve the ability to hit the right spot, so to collect reliable data. This work focuses on the development of an open hardware XYZ system based on 3D printers’ architecture and equipped with an imaging system. It demonstrates that the combination of image processing methods with the G-code generated during the movements of the XY axes can allows to avoid misalignment of the object that needs to be analysed, and thus to improve measurements’ spatial precision. The XYZ positioning system and the positioning calibration method are now tested on Modernist hydraulic tiles from Barcelona (Catalunya, Spain), a decorative and functional element in danger because of the estate speculation that is affecting the architectonic identity of the Catalan capital.