A polarizing microscope is a quick 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. 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. Jute also has tapered ends.

References about polarizing microscopy, preparation of slides and textile microscopic examination are

[1, 2, 3, 4]. Reference [5] is an interesting paper on the use of different textiles in canvases in French painting between  17th and 20th century. It shows that in the 18th century was mostly used hemp then in the 19th century came linen (flax) or mixed textiles of linen and hemp and eventually in 20th century cotton. It is a useful paper also in order to have an insight into methods to characterize textiles. A Reference specifically on English canvases is [6].

This is a video made to illustrate some fibers’ features as seen under a polarizing microscope.

This is my flowchart for preparing a textile identification report.

Microscopy textile flow chart

Flow chart for textile identification.
HHM (Hand-Held Microscope)
OM (Optical Microscopy)
PPL (Plane Polarized light)
CP (Crossed Polars)

[1] W. C McCrone (1982) “The Microscopical Identification of Artists’ Pigments” Journal of the International Institute for Conservation—Canadian Group 7 (1–2):11–34.

[2] N. Petraco, T. Kubic (2003) “Color Atlas and Manual of Microscopy for Criminalists, Chemists, and Conservators”

[3] B. Wheeler, L.J.Wilson (2008) “Practical Forensic microscopy”

[4] W. C. McCrone, L. B. McCrone, J. G. Delly (1978) “Polarized Light Microscopy”

[5] K. Vanderlip Carbonnel (1980) “A study of French painting canvases” Journal of the American Institute for Conservation, volume 20, number 1, article 1 (pp 03-20).

[6] R. D. Harley (1987) “Artists’ Prepared Canvases from Winsor & Newton 1928-1951” Studies in Conservation, Vol. 32, No. 2 (May), pp. 77-85.