Chapter 15 515 technical shine after both immediate application and a 24-hour duration on the hair. The magnitude of the attained benefit is again dependent on the nature of the hair, where obviously less sizable changes are obtained when using hair that already possesses a high level of shine (i.e. heavily pigmented hair). However, the magnitude of the technical benefit will also be dependent on the shine equation used (see Chapter 9), where the use of different expressions can actually alter conclusions regarding ordering of test treatments. This obviously unsatisfactory occurrence further illustrates the ambiguity associated with technical shine measurements. In theory, deposition of materials on the highly reflective surface of hair should lead to a reduction in shine, yet consumers frequently ascribe benefits to conditioning products. An answer to this apparent contradiction would seem to involve the hair array properties as opposed to those of single fibers. Namely, negatives associated with surface deposits on individual fibers may be outweighed by the ability to facilitate sleek, well-aligned styles. At TRI, we designed a Figure 15. Increase in hair shine resulting from application of a silicone shine serum