Effects of hair sprays on colour perception: a hyperspectral imaging approach to shine and chroma on heads
and
Ashland Specialty Ingredients, R&D, 1046 Route 202/206, Bridgewater, NJ 08807, USA
Received 7 June 2016, Accepted 14 August 2016
Abstract
OBJECTIVES:
Hair sprays apply fixative ingredients to provide hold to a hair style as well as weather resistance and optical properties such as shine. Generally, sprays distribute fine particles containing polymeric ingredients to form a thin film on the surface of hair. Dif- ferent hair types require different strengths of the formed deposit on the hair surface. The present study shows how sprays also alter the visibility of the hair colour by altering the surface topology of the hair fibres.
METHODS:
Hyperspectral imaging is used to map spectral charac- teristics of hair on mannequins and panelists over the curvature of heads. Spectral and spatial characteristics are measured before and after hair spray applications. The hair surface is imaged by SEM to visualize the degree of cuticle coverage. Finally, the perception of hair colour was evaluated on red-coloured mannequins by con- sumer questionnaire.
RESULTS:
Hair sprays deposit different degrees of fixatives, which lead to a progressive leveling of the cuticle natural tilt angle with respect to the fibre axis. As a result, shine is progressively shifting towards the region of hair colour visibility and decreases the per- ceived colour of hair seen by consumers. Lighter sprays show thin- ner film formation on the hair surface and less of a shine shift than strong hold hair sprays.
CONCLUSIONS:
Hair sprays are generally employed for hair style hold and weather resistance and considered without effect on hair colour. Our approach shows that spray-deposited films can affect colour perception by altering the microstructure of the hair surface. Thin films deposited on the hair fibre surface can partially fill gaps between cuticles, which reduces the cuticle natural angle. This par- tial erasure results in a angle shift of the shine regions towards the angle of internal reflection, thus decreasing the perceived hair col- our regions as experienced by a group of consumers.
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