Fig. 5From: Identifying plant fibres in cultural heritage with optical and electron microscopy: how to present results and avoid pitfalls© Lukesovaa The proper focus on the fibre’s top is crucial for the correct interpretation of interference colours of the modified Herzog test. The arrows show the differences in the focus on the fibre’s top and its edge. Figures b and c have the focus point underneath the top of the fibre.Back to article page