We have therefore built a dedicated NIR instrument, which enables us to measure spectra of paper-like flat objects efficiently and with low risk associated with object handling. The size of the instrument is 350 x 240 x 150 mm and the weight is less than 10 kg. This makes it really simple to transport even by airplane.
The instrument makes use of the wavelength interval 1100 - 2500 nm (9100 – 4000 cm-1).
Measurements are performed as is shown in the figure, the procedure is safe for the object and allows us to measure objects of different sizes. There is a safe distance between the object and the measurement aperture (2 mm in diameter) ensured by the smooth Perspex table. There is an automatic shutter system, which reduces the illumination time to less than one second, which is enough to record several hundred spectra and calculate an average spectrum.
The prototype was purpose-built for conducting surveys of large paper-based collections as it allows rapid object handling and data acquisition. During traditional surveys, subjectivity may influence the results. The instrumental approach is expected to both accelerate the surveying procedures and increase their reliability.
To see the instrument in action, please see the SurveNIR movie page.