Abstract 096
Effect of viewing background on visual perception of turbidity
J. Sens. Stud. 21 (1): 34-53, 2006
C.F. Fleet and K.J. Siebert
Colloidal size synthetic polymer microspheres of three sizes (0.15 µm, 0.31 µm, and 0.70 µm diameter) were each suspended in liquids of three different colors (clear, tan and dark brown) at a range of concentrations. Samples were presented to panelists in a viewing box. Visual threshold determinations were made for each of the nine sample sets using the Ascending Method of Limits and bright illumination (1192 lux) with each of three viewing backgrounds: black velvet, white cotton and white taffeta. Thresholds were much more similar expressed as turbidimeter observations than as either weight or number concentration. With the black velvet background the thresholds ranged from 0.206 to 2.19 NTU. With white cotton and white taffeta they were considerably higher, ranging from 1.97 to 41.0 NTU and from 2.97 to 34.4 NTU, respectively. This large difference appears to be a matter of contrast – scattered white light is much easier to perceive against a dark background.
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