Early work in the technical measurement of shine on Hair was conducted on individual hair fibers. A more consumer relevant measure of perceivable shine is obtained via the measurement of hair tresses. The Samba instrument provides a rapid measure of tress shine.

Principle of operation

Hair Shine Measurement

It is generally agreed in the industry that high shine is correlated with a prevalence of specular shine in the reflected light reaching the detector (or human eye). An image analysis technique has been answer to the technical measurement of shine [For example, McMullen and Jachowicz, J. Cosmet. Sci., 54, 335-351 (2003)]. The principle of measurement is based on the fact that when plane polarized light is incident on a reflecting material, the specular reflection maintains the original plane of polarization, whereas all other scattered light (termed the diffuse component) is depolarized [Bustard and Smith, Appl. Optics, 30, 3485-3491 (1991)]. Using polarized incident light, the detector measures the scattering profile with parallel and crossed polarizer in front of it. From such mapping, shine is calculated using various formulas in the literature [For example, Reich and Robbins, J. Soc. Cosmet. Chem., 44, 221-234 (1993), Keis, Ramaprasad and Kamath, J. Cosmet. Sci., 55, 49-63 (2004)].

Typical data output example

Figure 1: Typical Shine Data

A typical data output is shown in Figure 1, where the table shown can be toggled between the shine values using various formulas or the specular/diffuse reflectance analysis.

TRI testing solutions

The following is a typical test result obtained using Samba for demonstrating improvement in shine when dirty hair is treated with a product (Figure 2).

Figure 2: Typical Shine Results from Shampoo products

Figure 2 Typical result for a cleaning shampoo to show improvements in shine

Properties that can be measured

• Effect of products on tress shine, including that due to repeated application
• TRI has further improved the tress holder so replicate measurements on the same tress can be carried out
• The well aligned fiber arrangement that is possible using the TRI tress holder also assists in product performance differentiation. The loss in shine on perturbing the alignment of the tresses is much more for the poorly performing product