figure 120

clockwise half rotation of straw elements (sample 024) from a 1886 printing paper containing 20% kaolin (a). The kaolin shows more colour changes than the modern kaolin in the following sample, this is probably due to the thicker particles. The straw elements are a serrated epidermal cell (1), elongated barrel shaped parenchyma cell (2) and a rare hair cell (3). The 45º and 135º images show reversed colouring blue/yellow in the serrated epidermal cell, the reason for this is unknown [micrographs and z-stacks BvV].

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