Fig. 3

Undesired results in sediment plates: a Blurry texture, b Peeled off hole without stratification information, c Breakage of sediment plates along stratification d the back of the same plates repaired with fiber glass. e Sediment plate from Laacher See broken along draping ash layer. f and g Effect of illumination: Sediment plate from Tungurahua with adequate skirting light enhancing the stratification. g Inadequate frontal lighting without shadow effect