Paintings and Textiles

Polarization microscopes enable the detailed analysis of paint layers and pigments. Remove a tiny paint sample, place it on a slide and each crystal of pigment suddenly becomes visible, with whole layers of paint distinguishable from ground to surface. Which layers are original, and which have been added? Which colors are still in place and which need to be restored? A stereo microscope already answers most of these questions. 

For detailed structural and chemical analysis of paintings in cross-section, a scanning electron microscope (SEM) with energy dispersive X-ray spectrometer (EDX) is a must. This lets you bombard paint samples with electrons, studying the different energy characteristics of reflected x-rays, and revealing the chemical composition of the paint, thus enabling you to choose the best methods for restoration.

Being able to identify different fibers is important for the detailed analysis of textiles, paintings, upholstered furniture and other kinds of museum objects and artefacts, with applications including fields such as archaeology and forensics. Fibers usually have aged and are sometimes in fragmentary, decayed, charred or fossilized conditions. Careful, contact-free investigation is crucial for basic authentication, for assessing damage and identifying its causes, and for decisions on further treatment.

A polar­iz­ing micro­scope is a quick and efficient method to iden­tify tex­tiles such as paint­ing can­vases. To iden­tify com­mon his­tor­i­cal tex­tile such as cot­ton, hemp, wool, silk and flax you have to look at cer­tain fea­tures of the cloth’s fibers. For exam­ple, cot­ton is eas­ily rec­og­nized because its fibers show a char­ac­ter­is­tic twisted shape while hemp, jute and flax are pretty straight. Flax and jute are rec­og­niz­able because of their nodes, while jute also has tapered ends. Microscopes with detail-accurate high-quality optics ease the task of identifying the exact type of textile, particularly for damaged objects.

A modified Herzog test (red plate test) with a polarization light microscope is helpful for distinguishing natural and synthetic fibers, enabling more informed conclusions to be drawn about origin, age and methods of production. Pigment analysis provides information on the particular colors used to create a painting, and on which ones should be used in its restoration. Details become apparent about which paint layers are original and which have been added by previous restorers.

Confocal fluorescence microscopy offers a refined method to visualize textile yarns and fabrics at high resolution by removing out-of-focus light. It provides three-dimensional views of textiles and helps localize additives on and inside the fibers and textiles with high precision. This microscopy method offers geometric imaging of the yarn or the fabric at high magnifications and, by summation of images from various levels, it also provides a three-dimensionally constructed confocal image.