Learning



The notes deal with both the visible and invisible side of a work of Art including egg tempera & oil paintings, acrylic paintings, pastel drawings, gilt furniture. They focus on the underlayers of a work of Art and within them, on unstable & sensitive components undergoing chemical & physical change behind the deceiving appearance of the paint surface. The naked eye sees top coatings only.
The primary layers and their media components, require scientific tools. The naked eye reads the color, texture of the surface, abrasion, blemishes & visual disorder produced by the layers which result from chemical reactions. A work of Art is not static.
Often more than one degradation process is involved in the same work of art. The notebooks record observation conducted with specific tools.
They train your eye to see the visible and the concealed, and prepare you to the scientific research section.

The notes contain basic data that assess the main types of degradation and the observation of their chemistry process.


Read each layer by order of appearance from top to bottom.

Start always with the support which is prepared with a ground preparation to welcome the primary layers and intermediate layers,together with the top layers & coatings, in order to get a good cohesion and hopefully form a durable film. Impressionnists and modern painters started disrupting this order, as they did not always use ground preparation  or top coatings such as varnish. This proceed has been enhanced by contemporary paintings often void of any ground preparation and top coatings; They modified the potential of degradation of the media paint introducing new variables. Their ground preparation is made of synthetic  components which effects are under current study by major laboratories in the world.

A work of Art is composed of layers.

These layers are interacting with each other as well as the components within each layer.

Some pigments of the film paint are unstable and go through chemical change.

A painting is composed of superimposed layers with variable thickness and number.

Different interactions generate a variable degradation process in different areas of the paint film of a same work which require appropriate conservation care and restoration reversible treatment.

A layer may affect the adjacent layers.

Not all pigments have the same handling properties concentration of particles and depth distribution.

lead based pigments react with the binding oil producing white lumps or inclusions varying in size that can be seen on the paint surface when they are large.

The binding oil is affected by the presence of lead pigments which migrate through the paint film to the upper layers of the surface generating metal soap formation.

COMPONENTS & ANALYSIS
RESIN - DAMMAR - MASTIC

Target

simulate the future and understand the previous phasing of degradation.

Methodology of investigation

To provide data on molecular weight behavior occuring during degradation with the degree of fragmentation of the chain cleavage  leading to a change in plasticity causing yellowing, embrittlement & migration.

Scientific research- key issues

What type of oxidation products are formed?
How does degradation take place?
Is the varnish interacting with the layers underneath?
To what degree?
what happens when layers of varnish are between paint layers?
What about the former varnish residues embedded with dust and paint?
What about the imbibed varnish present in crusts on the surface?

What are the reactions to cleaning solvents?
How effective are the gel saturated tissues for safe removal?