How to Identify Pigments with Reflectance Spectroscopy

CHSOS just added a miniaturized spectrometer to its instrumentation. This system is equivalent to the ones tested already by CHSOS (Ocean OpticsBWTEK) and it will be used for pigments identification following the FORS (Fiber Optics Reflectance Spectroscopy) method. CHSOS chose a ASEQ LR1 spectrometer (300-1000 nm, 2nm resolution with 100um slit)   This spectrometer weights just 430 gr and features a Toshiba TCD1304DG linear array (3648 pixels).  I have to praise ASEQ for their amazing customer service which provided accurate samples tests and a fast reply to any of my questions. The method for the identification of pigments using a mini spectrometer equipped with fiber optics is called FORS (Fiber Optics Reflectance Spectroscopy). There is plenty of literature describing this methodology and presenting spectral database. This literature is specifically for this mini spectrometers:

[ws_table id=”7″]
reflectance spectroscopy for pigments

ASEQ LR1 spectrometer mounting a reflection fiber probe and a light source proved to be a valid system for  identification of pigments.


pigments checker v2 vsPigments Checker is for photographers, conservators and scientists interested in technical documentation of paintingss. It has 54 swatches of historical pigments designed for infrared photography, ultraviolet photography and other technical photographic methods for art examination. Check it out!

Pigments Checker is a collection of 54 swatches of his­tor­i­cal pig­ments that have been applied using gum ara­bic as a binder on a cel­lu­lose and cot­ton water­color paper, acids and lignin free. This paper is not treated with opti­cal bright­en­ers, it’s slightly UV flu­o­res­cent, and it reflects IR. Two cross-hair lines, 0,2 mm (ver­ti­cal) and 0.4 mm (hor­i­zon­tal) are printed on each swatch of paper before the appli­ca­tion of paint, in order to have a means to eval­u­ate the pig­ments’ trans­parency in the IR and IRR imag­ing. Among all the pig­ments and their vari­eties ever used in art these pig­ments col­lec­tion select the most used ones from antiquity to early 1950’.

reflectance spectroscopy FORS

The FORS system probe featuring 6 (600 micron core) excitation fibers and 1 (600 microns core) collection fiber.