[article]
| Titre : |
Hair shine : correlation instrumental and visual methods for measuring the effects of silicones |
| Type de document : |
texte imprimé |
| Auteurs : |
Isabelle Van Reeth, Auteur ; Virginie Caprasse, Auteur ; Stephanie Postiaux, Auteur ; Michael Starch, Auteur |
| Année de publication : |
2001 |
| Article en page(s) : |
p. 21-26 |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Catégories : |
Cheveux -- Soins et hygiène
Réflectance
Silicones -- Emploi en cosmétologie
|
| Index. décimale : |
668.5 Parfums et cosmétiques |
| Résumé : |
The attribute of hair shine is a very important, albeit elusive, quality whhich must be considered when evaluating the effects of a particular hair treatment. It is important for the cosmetic chemist to understand the effects of various hair treatments on shine because shine is strongly associated in the mind of the consumer with clean, healthy hair. Consequently, the measurement of hair shine is a critical part of performance evaluation for any raw material intended for use in hair care products. Silicone polymers are a class of raw materials that are effective for improving hair shine. Dimethicone and phenyl trimethicone, in particular, are often used for this purpose, but other types of silicones can also be effective. The selection of the best silicone for improving hair shine depends on the type of formula from which the silicone is to be delivered, so it is important to compare the effects of different silicones in the same formula.
In technical terms, hair shine is more accurately described as hair luster since it is associated with the appearance of stronglycontrasting, adjacent areas of light and dark (highlights). The light and dark areas arise from a phenomenon called specular reflectance, where the intensity of reflected light is highly dependent upon the angle between the observer and the light source. Specular reflectance is associated with smooth surfaces and this explains why it is associated with clean, healthy hair since both hair damage (surface roughness) and soiling reduce smoothness and therefore specular reflection. Several researchers have approached the problem of assessing hair shine by the use of a goniophotometer to measure reflected light intensity at various angles to a single hair fiber. This technique was used to study the relationship between luster and hair morphology, and the effects of various shampoo treatments. Other researchers have attempted to quantify hair luster using image analysis and data collected from hair tresses. Attempts to quantify hair shine in our laboratories have focused on the use of volunteers to evaluate hair tresses with the use of a "shine box". The shine box provides a means of controlling the illumination and observation conditions and is similar to a technique described by Reich and Robbins. Our shine box method was described in a 1995 publication. The shine box method has been used in our recent efforts to correlate data from human panels with objective measurements. Using a simple hand held meter to obtain gloss measuremsnts, we were able to show rough correlation between 60° gloss values and ranking scores from human panels using the shine box method.
Our work with the gloss meter showed that it was suitable for screening purposes, but it was relatively insensitive compared to the distinctions that are possible with the uman eye. Given this situation, we wished to continue the search for other objective methods. We also wished to expand our efforts to begin more close cooperation between our laboratories in Europe and the U.S. Both laboratories were using human panelists to evaluated hair shine using the shine box, but with different test designs. In the US, a ranking method was used, while a paired comparison method was used in Europe. The acquisition of an image analysis system and the establishment of half head (salon) testing capabilities provided further impetus to begin a joint project between our laboratories. Our goals were to develop better objective methods and to study the effects of various silicones on hair shine. |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10761 |
in IFSCC MAGAZINE > Vol. 4, N° 1 (01-02-03/2001) . - p. 21-26
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