AA&R is equipped in-house to perform a wide range of imaging and analysis techniques on paintings and other objects. For a look at our analytical equipment please go to our equipment guide.

On the imaging side we have our new purpose-built multispectral scanner, capable of producing not only highly accurate colour images, but also extending this into the ultra-violet and infrared with outstanding spatial resolution. Moreover we can also produce digital X-rays of paintings and conduct in situ analysis of paint using the integral X-ray fluorescence and Raman spectroscopic probes. Features of our scanner platform include:

• Positioning scanner. A five-axis (A/B and X/Y/Z axes) computer-controlled positioning system is accurate to 10 micrometres (.01mm) spatial resolution on all axes. Three axes (X/Y/Z) supply motion control to most of the imaging and analysis tools described below; two further axes (A/B) provide positioning for transmitted radiation sources such as X-ray and visible/infrared.
• High-performance colour/multispectral imaging. A Silicon CCD camera acts as the primary imaging system on our scanner. Combined with a novel monochromator system specially designed and built by AA&R, we can image entire paintings in a single pass at outstanding spatial (~400 pixels per centimetre) and spectral (10nm band) resolutions.
• Infrared reflectography. An InGaAs camera sensitive to wavelengths up to 1700nm enables study of features such as underdrawing. Combined with the Silicon CCD camera this forms a full multispectral system capable of giving extended spectral information at each pixel throughout the entire image.
• Digital X-ray. A 90kV microfocus source and 14-bit TDI detector provide the highest spatial resolution currently available on commercial digital X-ray systems. This replaces, and substantially improves on, the traditional film-based technologies that are rapidly going out of use in other fields.
• X-ray fluorescence. Our Bruker Artax 800 system is capable of determining elemental composition over an area of just 0.07mm. This makes analysis of individual brushstrokes strokes a simple matter and even permits measurement on larger pigment grains and agglomerates.
• Raman spectroscopy. Our dual-laser Bruker Senterra Raman system connects via a fibre-optic probe to give us full in situ characterisation of pigments. Combined with the element data from the X-ray fluorescence system, informed judgements about pigment identity without physical sampling.

Uniquely, the AA&R scanner platform combines all these techniques in a format that gives precisely correlated images and analysis data – any point within the painting area can be studied and directly compared at X-ray, ultra-violet, visible and infrared wavelengths, then analysed for elemental and molecular composition.In our laboratory we now have a suite of classic techniques for historical paint analysis implemented using the latest technology, such as:

• Polarised light and UV fluorescence microscopy. A research-grade polarised light microscope allows us to identify pigments and study paint cross-sections. With a fibre-optic spectrometer we can also measure spectral characteristics of individual pigment particles, simply differentiating otherwise confusing compounds.
• Scanning electron microscopy-energy dispersive X-ray spectrometry. Our scanning electron microscope enables us to determine the elemental composition of minute paint samples, as well as study particle shape using the XRD module.
• Fourier transform infrared spectroscopy. An imaging microscope and FTIR spectrometer allow us to look at the molecular structure of paint samples in exquisite detail.
• Raman microscopy. Our dual-laser Bruker Senterra Raman microscope helps us characterise the precise composition of pigments, differentiating sometimes problematic materials such as titanium dioxide whites.
• Gas chromatography-mass spectrometry. A GC-tandem MS instrument permits us to identify and characterise a huge range of organic materials used in paintings, including oils, resins and waxes. With a pyrolizer we can also study modern binding media, which is essential with twentieth century paintings.
• Liquid chromatography-mass spectrometry. Our GC-MS also operates as an LC-MS, a technique that allows us to analyse dyestuffs. In this way we can study not only dye-based pigments, but also the dyes on historical textiles.