Daphne De Luca

This postprints presents the articles of the fourth edition of RECH that took place in Split (Croatia) from October 20th to October 21st, 2017 and was jointly organised by members of the Escola Artística e Profissional Árvore, the Faculty of Fine Arts of the University of Lisbon, the Arts Academy of the University in Split, the Catholic University of Portugal, the Cinábrio and in the conservation-restoration field, selected 24 abstracts for communications and 16 abstracts for poster sessions, not all publish here. The titles cover a wide range of topics - from digital options for documentation, diagnosis and treatment, to new solutions and materials for filling and retouching of losses.

In this research project we propose a new material usable for the preparation of
retouching colours as an alternative to the more common watercolours normally
used for the pictorial restoration of the artworks. Compared to traditional Arabic
gum based watercolours, the self-produced colours here presented are made with
a new synthetic binder: Aquazol® 500. This polymer has good physical-chemical
properties and a wide spectrum of solubility in various organic polar solvents,
which also makes it suitable for the retouching of water sensitive artworks.
These new retouching colours with Aquazol® 500, prepared with two different recipes,
were investigated with different scientific analyses both before and after artificial
aging in a Solar Box, in order to evaluate their stability over time.
The results obtained from the study of the self-produced colours were then compared with those obtained from the same scientific investigations carried out on the only commercial watercolours based on Aquazol® currently on the market: QoR® by Golden Artist Colors (USA).
The results obtained from the study demonstrate that, thanks to its extreme stability, Aquazol® 500 can be considered a valid binder for retouching colours. In fact, the polymer does not degrade and does not show crosslinking phenomena.
The self produced colours are confirmed to be much more stable over time and therefore much more suitable than the QoR® watercolours for pictorial retouching of artistic artefacts.

Aquazol poly (2-ethyl-oxazoline) is a tertiary aliphatic amide, with physical and chemical properties that are exploited in a variety of ways, from pharmaceutical applications to the conservation of cultural heritage. In this study, we evaluated the use of Aquazol as a new binder for retouching paint in the restoration of artworks.

Aquazol 500 admixed with various formulations of organic red pigments was used to prepare paint replicas which were artificially aged and investigated by a multi-analytical approach based on analytical pyrolysis coupled with gas chromatography and mass spectrometry (Py-GC/MS), and thermogravimetry (TG), complemented by FTIR and LIBS spectroscopy. This is the first study on the ageing phenomena of Aquazol 500 using analytical pyrolysis and thermogravimetric analysis. The influence of the pigments' components on the pyrolysis behavior of Aquazol was also investigated.

The paint replicas did not show significant modifications during artificial ageing. This thus highlights the optimal properties of Aquazol 500 as a binder for retouching, in addition to its already established suitability as a filler or consolidant in the restoration of artifacts. Interestingly, when Aquazol 500 is used in formulations containing organic pigments, Aquazol-pigment interactions are observed, strongly depending on the pigment used.