Hélène Pasco

Institut Néel

Varnish layers are optical coatings that act as physico‐chemical barrier between the historical paint layers and the environment. Understanding how varnish materials protect historical paintings over time and in the presence of humidity or organic vapors is of central importance for art preservation. However, probing the behavior of varnish after a...

Gelled mediums were widely used during the nineteenth century, added to paint on the palette to modify its rheological, optical, and drying properties. Many variations of gelled mediums exist in the literature, all with the common basis of mastic resin or varnish, drying oil, and a lead compound. With the aim of unveiling the chemistry of such syst...

British 19th century painters formulated gelled systems often described as ideal paint mediums. These so-called megilps or gumtions are based on common paint materials like linseed oil, lead acetate, and mastic resin, and allowed painters such as J.M.W Turner to improve their paint's properties and achieve unprecedented effects in an age of innovat...

Mediums were used by painters in order to modify the texture and drying properties of their paint. During the 19th century, British artists developed a particular medium made of siccative oil, mastic resin and lead acetate trihydrate. The so-called “gumtions” form gel-like materials in a relatively short time, outperforming the existing paint media...

This research investigates and evaluates the optical, physical, and chemical interactions between a diammonium hydrogen phosphate (DAP) solution and seven pigments commonly encountered in archaeological and historic fresco and secco wall paintings and polychrome monuments. The pigments include cinnabar, French ochre, chalk, lapis lazuli, raw sienna...

The effectiveness of hydroxyapatite (HAP)-based treatment for the consolidation of a Hellenistic-Roman chamber tomb of Magara Tepsi at Athienou-Malloura in Cyprus was evaluated. Diammonium hydrogen phosphate was employed as the precursor enabling reactions with the calcium carbonate from the powdery marlstone to form HAP. DAP solutions were applied...

British 19th century painters such as J. M. W. Turner, commonly modified the properties of their paint by using gels called “gumtions”. These gels allowed them to easily tune the paint handling and drying properties. The fascinating properties of these “gumtions” were obtained by adding lead acetate to a ternary system based on mastic resin, linsee...

British 19th century painters such as J. M. W. Turner, commonly modified the properties of their paint by using gels called "gumtions". These gels allowed them to easily tune the paint handling and drying properties. The fascinating properties of these "gumtions" were obtained by adding lead acetate to a ternary system based on mastic resin, linsee...