Pigments are identified using portable XRF and by examination under a polarising microscope.
The chemical elements contained within a paint layer may be defined using portable X-Ray Fluorescence (XRF). This technique provides an indication of the pigments that may be present, which is particularly significant when looking for toxins in paint. The advantage of this technique is that it can be used on site providing immediate results.
The technique of polarised light miscroscopy (PLM) is normally required to precisely identify the pigments included in paint. Pigment particles are isolated from the paint medium and their optical characteristics defined under a Leica Polarising Microscope fitted with high quality camera providing exceptional image quality. Pigment identification helps us to define the age of paint layers.
Two example images are provided here for the blue pigment azurite: under plane polarised light and crossed polars.