# Authentication of a Painting by [PERSON] Using Modern Multi-Analytical Methods
## 2 Experimental
### Methods, Techniques, and Devices Involved in the Expertise  
Along with the visual analysis with magnifying instruments (manual magnifiers) and stereo microscope (STEREO MX4, 10X-220X), a series of high-resolution mobile devices and instruments were used, of which we mention [1, 20, 21, 22, 23, 24, 25, 26, 27, 28]:  
* Forensic magnifier, with USB port, HS525A series, made by SZZCX Company, China, 2016 model, 30-50\(\times\) magnification with UVA (365 nm), UVC (254 nm), Infrared (IR 850 nm, 940 nm), White-blue (470 nm), white-green (550 nm), Laser (980 nm). View area: 12-9 mm. * Digital microscope with USB power supply, 1.3 MP (2.0 MP interpolated), model Discovery DX-1, made by Veho, China. Manual focus from 10 to 500 mm, frame rate: max 30 f/s under 600 lx brightness, eight white LEDs with adjustable lighting. Magnification rate from 20\(\times\) to 200\(\times\), AVI video format. * Portable UV lighting device, with LED, G5, 4W UV. Model no. EGHHUV4, made by Voila, China. Additionally, for the determination of chemical and physical-structural characteristics, scanning electron microscopy coupled with X-ray spectrometry (SEM-EDX), high resolution optical microscopy, and \(\mu\)-FT-IR spectrophotometry were used. SEM-EDX Microscopy. The analysis used a scanning electron microscope (SEM) model VEGA II LSH, produced by TESCAN Czech company, coupled with an EDX detector type QUANTAX QX2, produced by BRUKER/ROENTEC Germany. The microscope, fully computer controlled, has a tungsten filament electron gun, which can achieve a resolution of 3 nm at 30 kV, with magnification power between 30\(\times\) and 1,000,000\(\times\) in \"resolution\" operating mode, acceleration voltage between 200 V and 30 kV, scan speed between 200 ns and 10 ms per pixel. The working pressure is less than \(1\times 10^{-2}\) Pa. The image obtained can be made up of secondary electrons (SE) or back-scattered electrons (BSE). Quantax QX2 is an EDX detector used for qualitative and quantitative micro-analysis. The EDX detector is of the third generation, type X-flash, which does not require liquid nitrogen cooling and is about 10 times faster than conventional Si (Li) detectors. The technique, together with the visualization of the microphotography, allows the image to be reproduced with the mapping (arrangement) of the atoms on the investigated surface. Based on the EDX spectrum, the determination of the elemental composition (in gravimetric or molar percentages) of a microstructure or of a selected area, was made. \(\mu\)-FT-IR Spectrometry. For \(\mu\)-FTIR analysis an FT-IR spectrophotometer coupled to a Hyperion 1000 microscope was used, both produced by Bruker Optik, Germany. The FT-IR spectrophotometer is a Tensor 27 model, which is foremost suitable for measurements in the near IR. The standard detector is DLaTGS, which covers the spectral domain 7500-370 cm\({}^{-1}\), and works at room temperature. The standard resolution is 4 cm\({}^{-1}\), but it can also reach 1 cm\({}^{-1}\). Tensor 27 is fitted with a He-Ne laser, which emits at 633 nm and a power of 1 mW, presenting a Rocksolid alignment of the interferometer. The signal/noise ratio of this spectrophotometer is very good. Tensor 27 is fully controlled through the Opus software. The Hyperion 1000 microscope is an accessory that can be coupled with almost any FT-IR spectrophotometer produced by Bruker. For fully nondestructive readings, the Tensor 27 spectrophotometer is coupled to the Hyperion 1000 microscope; usually, for solid samples, the work is done in reflectance mode. The software used is Opus/Video, for the acquisition of interactive video data. It is possible to work both in transmission and reflection modes. The detector is an MCT type, cooled with liquid nitrogen (-196 \({}^{\circ}\)C). The spectral domain in which the work was carried out was 600-4000 cm\({}^{-1}\). The microscope is fitted with a \(\times\)15 lens. Optical microscopy. In optical microscopy analyses, a Zeiss Imager a1M microscope is used, which has an AXIOCAM camera and specialized software attached.