3D scientific visualisation of 19th century glass replicas of invertebrates

The Leopold and Rudolf Blaschka replicas of ma- rine invertebrates are among the more famous objects produced in the XIXth century for pedagogical purposes. Their high level of detail, still unknown manufacturing technique and their con- ceived artistic beauty, make these glass replicas precious museum exhibits currently. The fragility of these items produced by the Blaschka family (father and son) poses challenges for their preservation, study and presentation to the public. Moreover, their complex reflectivity and materiality (painted glass, coloured glass, glass and metal, etc.) presents a particularly interesting 3D digitisation challenge. The paper reports first results of such doumentation, performed on selected artefacts from the collections of the Fondazione Scienza e Tecnica in Florence, Italy and the zoological Section “La Specola” of the Natural History Muse- um of the University of Florence, both inaccessible to the public nowadays. The method applied consists of portable photogram- metry, using polarised light sources. The obtained 3D models are accurate digital surrogates of the originals, returning geometrical features and precise color information, and can be used for scientific purposes (measurements and visual observations), pedagogical purposes or presentation to the wide public in virtual exhibitions.