An overview is given of non-tabular crystals with {111} surfaces occurring in emulsions of silver bromide and silver chloride tabular grains. The crystal defects are characterized by transmission electron microscopy (TEM) and their influence on the growth process is discussed. It is proven that in all cases of non-tabular growth twins on two non-parallel {111} type planes are present. Different morphologies have been observed in AgBr and AgCl emulsions. The most frequently occurring morphologies are needle and tetrahedron shaped crystals in AgBr and thick tabular crystals with an incomplete microtwin as well as crystals consisting of a tetrahedral shaped part and a flat triangular to trapezoidal part in AgCl. A comparison will be made between the silver bromide and the silver chloride crystals.
W. Van Renterghem, C. Goessens, D. Schryver, J. Van Landuyt, D. Bollen, R. De Keyzers, C. Van Roost, "Influence of Twinning on the Morphology of AgBr and AgCl Microcrystals" in Journal of Imaging Science and Technology, 2001, pp 349 - 356, https://doi.org/10.2352/J.ImagingSci.Technol.2001.45.4.art00006