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Light scattering and shine measurements of human hair: A sensitive probe of the hair surface
Abstract
In this paper, an instrumental method for measuring hair shine is presented and shown to exhibit excellent correlation with a large series of subjective evaluations of shine. In addition to providing shine values, the light-scattering methods developed are shown, in many cases, to provide a sensitive means of following changes to the hair surface, including deposition (soiling), particle removal (cleaning), and even interactions on the fiber surface. Employing the developed methods, the effect of washing hair tresses with a series of commercial shampoos is investigated. The effects examined are shown to fall into three classes: Shampoos without highly substantive ingredients left hair in its cleanest and shiniest state. Shampoos containing ingredients substantive to hair (polycationics and soap) left deposits on the fiber surface and dulled the hair. The worst dulling was observed when particles deposited on the hair from one shampoo formed a complex with particles contained in a second product.
... [10][11][12] Regardless, most of our current understanding of the optical properties of hair comes from the very first published studies by Stamm et al. 10,11 During this time-and in some cases even nowadays-most laboratories performed luster measurements utilizing a goniophotometer. [10][11][12][13][14][15][16][17][18][19][20] It is an instrument capable of measuring the spatial distribution of radiation-more specifically, the angular distribution of visible light reflected from a substrate. This very accurate technique can be employed to examine single hair fibers or even an array of fibers. ...
... This idea was first proposed by Reich and Robbins in goniophotometric studies and later adapted by McMullen and Jachowicz for imaging work. 20,24 Lefaudeux et al. proposed deconvolution of the specular peak so that only the portion of the peak within the dashed lines is integrated as S. 26 Such an approach assumes that the far ends of the specular reflection curve, in fact, contribute to diffuse reflection. While many studies have been carried out in the last fifteen years using image analysisbased luster measurements, there has yet to be any inter-laboratory comparison of luster values obtained by one technique with another. ...
... different pigment types, cosmetic treatments, sebum, etc.) and correlated well with subjective panel evaluations. 20 Another model, employed by Guiolet et al., simply takes the ratio of specular to diffuse reflection. 12 ...
Many visually perceptible phenomena are observed in hair. Such attributes arise due to the intrinsic properties of hair as well as the geometrical, three-dimensional arrangement of fibers into an assembly. For example, hair luster has an intrinsic component (the optical properties of the fiber) and an extrinsic component evolving from the alignment of fibers and their collective reflection. In this chapter we will introduce imaging techniques, mostly in the context of digital photography, which can be used in conjunction with image analysis procedures. In going about such a task, we must first discuss some introductory concepts about image analysis as well as the optical properties of hair. A significant portion of this chapter is dedicated to hair luster; however, we will also discuss hair volume, fixative flaking, measurement of fiber orientation by two-dimensional Fourier transform, hair curliness, hair color, and the analysis of eyelashes.
... It is, however, difficult to describe and measure in a quantitative way. Many formulae and methods have been suggested to quantify luster [34,[40][41][42][43]. In general, reflection from a surface into backward directions consists of specular and diffused light. ...
... The larger the intensity ratio of specular to diffused light is, the higher the luster is. Luster is also strongly dependent on the angular distribution of reflected light [42,43]. The sharper the angular distribution of reflected light is, the higher the luster is. ...
In the beetle Goliathus cacicus, male elytra show silky luster with iridescence while female ones appear lusterless white without iridescence to our perception. We revealed by structural characterizations and optical measurements that elytral coloration and luster of both male and female beetles stem from the tubular scales on the elytra, whose interior is filled with a random structure. Distinct differences between male and female scales reside in the cortex thickness and the filling fraction of the random structure, which are important factors in the determination of the sexual dichromatic luster and iridescence. In additional to reflection peaks in the visible range, spectral measurements indicate that both male and female elytra display also strong iridescent ultraviolet (UV) reflections. Scattering spectra show that both male and female elytra display UV luster, although it is absent for female ones in the visible range.
... Further approaches have been color measurements (7) and image analysis (e.g., 8). In parallel, the common laboratory practice for screening products is to use expert or consumer panels to subjectively rank hair luster, e.g., by means of a "shine box" (6,(9)(10)(11)(12). Noteworthy is the approach by Tango and Shimmoto (13) to develop a method and a device for the in vivo determination of hair shine that is related to the principles of commercial "gloss meters" (10,14). ...
... When appreciable hair gloss is generated, i.e., when the peak for specular reflection starts to dominate the GP curves, which occurs around G L > 20-30%, a largely linear relationship is observed, as marked in Figure 5, which corresponds to Reich and Robbins' observation (11). In this view, the hypothesis that the gloss index is a valid measure for hair luster that correlates with the consumer's perception of hair shine is further corroborated. ...
Hair shine or luster is perceived as an important, though analytically somewhat elusive, attribute of beauty, primarily associated with clean and healthy hair. Principles for the assessment of hair luster are developed that are consistent with the practical situation. These principles are related to the components of light, specularly and diffusely reflected from single hair fibers, as measured by laser-based, multiangle goniophotometry, presented in Part I. Considering various definitions of gloss, their tradition, practical implementation, and their inherent limitations for testing hair, the gloss index as a physically consistent measure of hair luster is derived from the ratio of the integral intensities of the light components. Changes of the parameter values along hair length, namely their decrease, are analyzed for hairs of different color and ethnic origin. The correlation with shine evaluations of hair tresses by panels, based on literature data, is analyzed and ascertained.
... Experimentally, the BRDF is measured by gonio-spectrophotometry, measuring the quantity of light reflected in each space direction, i.e. as a function of incident and observation angles ("gonio"), possibly depending on light wavelength ("spectro"). This method is widely used in the literature to characterize the light scattering properties of various materials, for examples hair [28], leaves [29] [30], tinfoil [31], glass [32] and skin [33]. At first order, the way a surface scatters light (and therefore its BRDF) depends on its roughness: the rougher the surface, the higher the light diffusion [34] [35] [36] [37]. ...
The evolution of visual aspect of polymers with wear is a fundamental problem in numerous industries. In this article, we study the visibility of scratches. Fifty parallel micro-scratches are performed on three samples differing only by their values of gloss. Scratches are much more visible on glossy samples than on mat ones, in agreement with previous works. To interpret these results, a bidirectional reflectance distribution function (BRDF) model is developed to compute the way a surface scatters light based on a roughness measurement described by a distribution of microfacet orientations. In this paper, this BRDF model is applied to investigate the influence of the scratches on the light scattering properties of a surface. Roughness measurements are performed on the surfaces before and after scratching. Then, the BRDFs are computed and compared to each other. The visibility of scratches strongly depends on how much they modify the roughness slope distribution function of the surface. Depending on the initial gloss of the surface, this leads to more or less contrast. Finally, a visibility criterion is proposed based on this contrast effect.
... Although this measurement is very rich, it is time-consuming because all the space directions must be scanned. This function is often measured in the literature to study the optical properties of materials (hair [16], leaves [17,18], tinfoil [19], glass [20], skin [21] …). ...
Polyurethane coatings applied on PVC flooring substrate may influence its optical properties, especially gloss. Basically, rough surfaces look matte while smooth ones look glossy. However, the quantitative link between roughness and gloss remains insufficiently modelled. In this article, a microfacet-based model which predicts the BRDF from the 3D roughness slope distribution function f(dz/dx,dz/dy) is developed. Contrary to the different models existing in the literature, the computations are based directly on measured roughness from which the local slope distribution function is extracted. The model is applied to eight polyurethane coatings with different roughness and gloss. The results of the computations are compared to BRDF and gloss measurements. It is shown that this approach allows a good prediction of optical properties. In particular, the model predicts remarkably well the measured 60° gloss values.
... paint), however, such devices do not satisfactorily measure the surface lustre of highly anisotropic surfaces such as parallel fibre bundles or single fibres. Although goniometric techniques have been developed [1,2,3,4], the Rotating Light Table (RLT) herein described offers an alternative technique that has a range of applications. The RLT was originally developed to quantify the light reflection properties before and after a continuous cotton-sliver mercerising treatment. ...
The Rotating Light Table (RLT) is a light-reflective device developed to measure the surface lustre of fibres in various forms – as bundles containing many parallel fibres (e.g., in top form), as small groups of parallel fibres, or even as single fibres. Such fibres may be un-dyed (white/cream), dyed, or naturally coloured. The device can compare the relative lustre of fibre bundles before and after undergoing surface modification. Comparing the surface lustre of cotton sliver before and after mercerisation exemplifies the technique. Surface reflectance profiles from ≤20 parallel-mounted human hairs orientated root-to-tip, and from single black or light-coloured fibres, further exemplify the precision and sensitivity of the technique.
... Allgemein gilt, dass der Glanz mit zunehmendem spiegelnden Anteil größer und mit zunehmendem diffusen Anteil kleiner wird. Robbins und Reich [35] schlagen folgende Beziehung zur Ermittlung des Haarglanzes vor: L = S/DW ( 1 2 Abb.16: ¨ Anderung des Torsionsmoduls in Abhängigkeit von der rel. Luftfeuchte bei Haaren mit und ohne Dauerwelle. ...
Im folgenden wird eine Übersicht über die geometrischen und physikalischen Eigenschaften von Haaren gegeben. Unter geometrischen Eigenschaften werden die axiale und die radiale Struktur, sowie die Haarlänge verstanden. Die physikalischen Eigenschaften umfassen die Zug-, Biege- und Torsionssteifigkeit, viskoelastisches Verhalten und Hysterese, sowie den Einfluss von Feuchtigkeit, Temperatur und kosmetischen Behandlungen auf eben diese Größen. Dazu zählen au�erdem die Reibung und die optischen Eigenschaften.
... Variables and functions suggested by several hair fiber and textile scientists all pursued the goal of obtaining the best correlation with visual judgments of gloss. Reich and Robbins (1993) reported very good agreement between subjective rankings and instrumental mean values based on single fiber measurements (Spearman rank correlation coefficient = 1), but no details were given. Czepluch et al. (1993) examined the light reflection from hair strands, and they reported without further details that the gloss evaluation of different testers correlated with the concerned optical variables. ...
In mink production, silkiness refers to a silky fur surface. The sensory evaluation of silkiness may be based on information perceived by the eyes and the hands. Silkiness is assumed to depend on hair fiber properties such as guard hair straightness, glossiness, and smoothness. Our objective was to characterize the dorsal surface of brown mink pelts by means of optical variables and relate these to the visual grades of silkiness, thereby forming some objective criteria of silkiness. Two groups of brown male mink pelts (winter coat) that originated from a selection trial with a focus on silkiness were used. The pelts came from a basic (Group 1992) population and a selected (Group 1994) generation. Group 1992 was graded visually on a scale from 1 to 6 (most silky); Group 1994 was graded on a scale from 1 to 8 (most silky). With goniophotometric, nondestructive methods, the reflectance from each pelt surface was measured describing the angle-dependent distribution of reflection in the shape of angular reflectance curves. The measurements were performed along (w-reflectance curve) and across (c-reflectance curve) the guard hairs. The w-curve included a maximum assumed to be related to silkiness. Specular gloss, indicated by the maximum reflectance (s) in the direction of mirror reflection, was positively correlated with silkiness. For Group 1994, s = 72.94 + .49 x silkiness; r2 = .33, P = .0003. Correspondingly, an area representing specular (S) plus diffuse (D) reflectance (S + D) under the curve was positively correlated with silkiness. A decreasing band width of the w-curve at 90% of maximum specular reflectance (w90) was related to an increase of silkiness (Group 1992: r = -.50, P < .01). Furthermore, both s/w90 and (S + D)/w90 were positively correlated with silkiness (Group 1992: r = .49, P < .01 and r = .51, P < .01, respectively). Measures of contrast gloss involving relations or differences between specular and diffuse reflectance were not suitable. From our results, a high degree of specular gloss, indicated by s, explained and was related to an essential part of silkiness and general sensory quality of the pelts investigated. Also, s was relatively easy to measure. Thus, even if the objective variables did not correlate perfectly with visual judgments, s was considered to be the most usable objective variable in characterizing silkiness.
Image analysis performs the quantitative extraction of information from the captured image by means of dedicated software taking into account spatial and spectral calibrations. This chapter provides the reader an overview of the most important types of imaging approaches and the nature of the information obtained. The optical imaging techniques will be separated by their information content, with the main types being classical reflectance imaging, fluorescence imaging, time‐resolved imaging, hyperspectral imaging, confocal imaging, and interferometric imaging. The chapter explores in more detail the macroscopic and microscopic imaging approaches used in the characterization of pyrrolidone‐ and caprolactam‐based materials. Seven main fields of application have a long history of using pyrrolidone‐based compounds: printing, medical applications, bio‐materials, antibacterial films and coatings, filtration, energy and electronic applications, and personal care/home care. Polymers help in the care of the surfaces and their protection against attacks of sugars and acids.
Background
The concept of hair transparency has been claimed widely in the Japan (and now it is spreading to Asian) hair color market. Despite the general use of this concept, to date, there is no clear and objective description to accurately explain what it is. In this work, we have decoded and gave clarity to the concept of hair transparency via a technical model (validated for both Japan and China markets) composed of measurable parameters of hair property using a single device.
Methodology and Results
A comprehensive study composed of various tests was used, starting with a qualitative identification of key parameters via in‐depth workshop discussions with over 40 Japanese stylists and a panel of 12 consumers. These identified parameters (luminosity, color visibility, and Shine) were then translated into technically measurable parameters of the hair fiber (Diffused light intensity, ratio of RGB channel intensities of Diffused light, and luster) via a single instrument—Hair SAMBA (a dual‐polarized imaging system). Afterward, 10 carefully selected anchor shades were used as visual stimuli in an online pairwise comparison (PC) study with 100 Japanese stylists to generate quantitative transparency perception data of the swatches. Technical parameters of these swatches were measured by SAMBA and consolidated with the PC output, for the creation and validation of the mathematical model. After, with another PC study (N = 100) in China, with seven shades from Japan study and 6 additional Chinese market shades, the applicability of the model in China market was validated.
Conclusion
We have clarified and quantified the concept of hair transparency through a consumer centric approach and with objective data. Our findings will enable the development of optimum transparent shades which better suits consumer needs. Lastly, we would like to highlight the beauty of digitalization in the study: The digital evaluation pathways chosen allowed us to collect quantitative consumer data from two countries for the creation of a robust model under the impact of COVID‐19 and would definitely be the way to go for our future consumer evaluation studies.
Objectives:
The hair surface condition underlies many visually perceived attributes such as shine, color, and the 3D perception of a curly hair style. Many factors can alter the hair surface such as cumulated cleansing/styling regimens or chemical treatments which can lead to degradation of the cuticle edges and surface. Similarly, pollutants, sebum, and shampoo / conditioners can build up on the hair surface which are also perceivable to an observer.
Methods:
The highly directive light of a laser is reflected and scattered by the surface of hair fibers into a circular pattern. The angular and spatial characteristics of this pattern reflect the hair geometry and the quality of the hair surface, i.e. the outer cuticle layer. Dark flat hair tresses were used to measure the impact of artificial sebum and shampoo / conditioner regimens on the cuticle surfaces. Also, longer single hair fibers from 4 volunteers were characterized for their surface changes from roots to tips, i.e. over the chronological age of the hair.
Results:
The laser scattering shows clear changes in specular reflection characteristics from treatments and allows for the extraction of the cuticle inclination angle with respect to the hair axis. Deep cleansing or clarifying shampoos do partially restore the cuticle angle by removing residues on the hair surface while more conditioning systems can lead to changes in specular reflection angle and scattering, especially when multiple cycles of shampoo + conditioner treatments. Lastly, changes in hair surface can be traced over time of hair age by this approach and are consistent with frequency and nature of hair treatments.
Conclusions:
The method shows great potential for characterizing cleansing regimens in terms of their impact on the hair surface, either as single or multiple washes. Coverage or damage to the hair cuticles appears readily as an angle shift of the specular reflection while the quality of the surface topology has a direct impact on the angular width of the specular reflection thus affecting the shine band on a person's head. Hair aging from root to tip can be quantified by laser scattering and correlates well with treatment events in time.
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. Different 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 color by altering the surface topology of the hair fibers.
Methods:
Hyperspectral imaging is used to map spectral characteristics 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 color was evaluated on red colored mannequins by consumer 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 fiber axis. As a result, shine is progressively shifting towards the region of hair color visibility and decreases the perceived color of hair seen by consumers. Lighter sprays show thinner 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 color. Our approach shows that spray deposited films can affect color perception by altering the microstructure of the hair surface. Thin films deposited on the hair fiber surface can partially fill gaps between cuticles which reduces the cuticle natural angle. This partial erasure results in a angle shift of the shine regions towards the angle of internal reflection, thus decreasing the perceived hair color regions as experienced by a group of consumers. This article is protected by copyright. All rights reserved.
Herein is an attempt to bridge the gap between consumer and scientist by defining the more important consumer hair assembly properties (heads of hair, tresses, or wigs) describing how these properties are affected by changes from cosmetic treatments to fundamental single fiber properties. The effects of changes in single fiber properties by chronological age for five different stages of one’s life is also described in terms of how these fiber properties relate to and affect the important consumer hair assembly properties. The literature on hair breakage is also summarized as a multifactorial phenomenon involving tangle formation with hairs looped over other hairs, severe bending deformations, highly localized stresses, and the amount of water in the fibers. The effects of hair curvature, fiber twists, knots, hair damage and abrasive wear on hair breakage are also described. A new unpublished section describing split hairs found on the heads of consumers is described along with preferred mechanisms for the formation of these different types of split hairs.
There is perhaps a misconception that hair-care products are mere commodities of a simplistic nature: technologically limited and lacking the sophistication of skin care products. Nothing, in fact, could be further from the truth. As stated by one of the world’s leading authorities in hair care, Dr. Rodney Dawber, Emeritus Clinical Reader at Oxford, ‘Shampoos represent the ultimate in simplicity from complexity. A product everyone can use anywhere, any when, and expect to achieve the same result’.
The effectiveness of cleaning soils typically found on human skin and hair is dependent upon the nature of the soils. Oily soils like sebum generally require mixtures of surfactants and cosurfactants and foam boasters to "roll up" and lift the soil from the surface of the skin and hair. Solubilization of the oil and formation of an emulsion also participates in cleaning, especially when fatty acids are present in the cleansing solution. Emulsification involves breaking a large oily droplet into smaller particles, followed by formation of a stable suspension in the aqueous cleansing solution. Two parameters are considered in this chapter in relation to surfactant interactions with stratum corneum: binding to the membrane and membrane swelling. Within these contexts, the impact of surfactant solution properties, the role of pH, and interactions in mixed surfactant systems with stratum corneum are discussed with relevance to skin irritation. The strategies to balance cleaning and mildness to the skin are challenging at best. The trend has been to move to ether sulfates and milder cosurfactants like nonionics and amphoterics in skin cleansing formulations. Manipulation of the monomer composition to potentiate inclusion of the irritating surfactant species within the micelle using additives is a future strategy that needs investigation.
Shine (luster) is one of the most sought-after and desirable criteria for a hair care product, including hair styling. The purpose of a hair fixative polymer is to hold the hair style in place. In order to deliver hair shine, silicone is typically added as a separate ingredient in the formulation. However for the amount of silicone required to deliver shine to the hair in a hair styling or fixative product, the hold performance of the fixative polymer becomes compromised. This study describes the development and results of the Styrene/Acrylates Copolymer hair fixative that delivers both hold and shine to the hair, and the polymer properties behind it.
Hair health is a core benefit of products produced for consumers by the cosmetic industry, and more than 70% of women claim to want healthy hair. However, there is very little clarity in the industry as to the meaning of healthy hair in a consumer context and the technical factors that control what the consumer perceives as hair health. Providing updated information on how to prevent and restore hair damage, Healthy Hair characterizes the clinical, physical, and chemical properties of healthy hair. Factors that control a woman’s perception of healthy hair are described, and how these factors link to the fundamental biology of the hair fiber are explained, as well as insults to hair, such as brushing, coloring, and UV exposure. The influences of different products on hair health are discussed, and methods used to measure healthy hair at the molecular, single-fiber, and consumer levels are described. Hundreds of high quality color pictures illustrate the most important clinical, dermoscopic, and microscopic characteristics of both healthy and unhealthy hair.
Poly(vinyl alcohol) has been functionalized with aldehydes in tetrahydrofuran (THF) with a good control of the grafting. A wide library of poly(vinyl acetals) could be obtained in order to study some structure/property correlations. The influence of the aldehyde nature on the functionalization rates has been studied, in particular for optical properties by measurement of the shininess for further applications in the cosmetic field. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40677.
Human hair is the subject of a remarkably wide range of scientific investigations. Its chemical and physical properties are of importance to the cosmetics industry, forensic scientists and to biomedical researchers. The fifth edition of this book confirms its position as the definitive monograph on the subject. Previous editions were recognized as “concise and thorough” (Journal of the American Chemical Society), “an invaluable resource” (Canadian Forensic Science Society Journal), and “highly recommended” (Textile Research Journal). Chemical and Physical Behavior of Human Hair is a teaching guide and reference volume for cosmetic chemists and other scientists in the hair products industry, academic researchers studying hair and hair growth, textile scientists and forensic specialists. Features of the Fifth Edition: Recent advances in the classification and characterization of the different proteins and genes in IF and keratin associated proteins in human hair are described. The mechanism and incidence of hair growth and loss and hair density vs. age of males & females are described for Asians, Caucasians and Africans in different scalp regions. Details of hair surface lipids and cuticle membranes provide a better understanding of the surface and organization of the CMC and its involvement in stress strain is presented. Recent evidence demonstrates a more bilateral structure in curly hair and a more concentric arrangement of different cortical proteins in straighter hair. SNPs involved in hair form (curl and coarseness) and pigmentation and genes in alopecia and hair abnormalities are described. The latest biosynthetic scheme for hair pigments and structures for these and the different response of red versus brown-black pigments to photodegradation is described. A new method for curvature on 2,400 persons from different countries and groups is used to assign curvature throughout this book. Additional data for age and effects on diameter, ellipticity, elastic modulus, break stress and other parameters are presented with much larger data sets featuring statistical analyses. Hair conditioning, strength, breakage, split ends, flyaway, shine, combing ease, body, style retention, manageability and feel parameters are defined and described. A new section of different life stages by age groups considering collective and individual changes in hair fiber properties with age and how these affect assembly properties.
The authors developed and qualified an automated routine screening tool to quantify hair shine. This tool is able to separately record individual properties of hair shine such as specular reflection and multiple reflection, as well as additional features such as sparkle, parallelism of hair fibers, and hair color, which strongly affect the subjective ranking by individual readers. A side-by-side comparison of different hair care and styling products with regard to hair shine using the automated screening tool in parallel with standard panel assessment showed that the automated system provides an almost identical ranking and the same statistical significances as the panel assessment. Provided stringent stratification of hair fibers for color and parallelism, the automated tool competes favorably with panel assessments of hair shine. In this case, data generated with the opsira Shine-Box are clearly superior over data generated by panel assessment in terms of reliability and repeatability, workload and time consumption, and sensitivity and specificity to detect differences after shampoo, conditioner, and leave-in treatment. The automated tool is therefore well suited to replace standard panel assessments in claim support, at least as a screening tool. A further advantage of the automated system over panel assessments is the fact that absolute numeric values are generated for a given hair care product, whereas panel assessments can only give rankings of a series of hair care products included in the same study. Thus, the absolute numeric data generated with the automated system allow comparison of hair care products between studies or at different time points after treatment.
In this study, digital photography in combination with image analysis was used to measure the luster of several lipstick formulations containing varying amounts and types of polymers. A weighed amount of lipstick was applied to a mannequin's lips and the mannequin was illuminated by a uniform beam of a white light source. Digital images of the mannequin were captured with a high-resolution camera and the images were analyzed using image analysis software. Luster analysis was performed using Stamm (L(Stamm)) and Reich-Robbins (L(R-R)) luster parameters. Statistical analysis was performed on each luster parameter (L(Stamm) and L(R-R)), peak height, and peak width. Peak heights for lipstick formulation containing 11% and 5% VP/eicosene copolymer were statistically different from those of the control. The L(Stamm) and L(R-R) parameters for the treatment containing 11% VP/eicosene copolymer were statistically different from these of the control. Based on the results obtained in this study, we are able to determine whether a polymer is a good pigment dispersant and contributes to visually detected shine of a lipstick upon application. The methodology presented in this paper could serve as a tool for investigators to screen their ingredients for shine in lipstick formulations.
The ethnic hair care market is large and diverse, with many unmet needs, especially when the definition of ethnic varies as much as the hair does. By examining the variety of hair care raw materials now available, we designed hair styling formulations for targeted benefits such as anti-frizz, conditioning, style control, humidity resistance, UV protection and color loss protection. We have characterized three distinctive hair styling formulations targeted to specific multicultural needs. This has been completed by using standard personal care laboratory evaluations including the Diastron Limited (TM)Miniature Tensile Tester for stiffness, the Bossa Nova Technologies (TM) Shine Instrument, high-humidity curl control, UV exposure, and expert panel evaluations; the results were substantiated using current state-of-the-art analytical tools, including atomic force microscopy and scanning electron microscopy. Results demonstrate that a varied product portfolio is required for such a diverse market segment. Styling products ranging from alcoholic sprays, leave on styling creams or gels and styling curl activators offer performance attributes that can be utilized on a variety of hair types such as Asian, African, Caucasian and Brazilian.
J. Cosmet. Sci., 60, 153–169 (March/April 2009)
Hair luster is one of the most important parameters of visual appearance perceived by consumers. Current luster formulae (TRI, Reich-Robbins, ...) are optimized for goniophotometric measurements. They are based on a mathematical decomposition of reflected light into specular and diffused light and the measurement of the shine peak width on the fitted angular distributions. In this expose, we are describing a polarization imaging system measuring luster of hair tresses with an innovative algorithm. Using polarization imaging allows to physically separating the specular light from the diffused light for each pixel of the imaged tress. Angular distributions of the specular and diffused light are obtained in a few seconds. Where conventional methods calculate the shine peak width on the angular distribution, the imaging system imitates the human eye and calculates the shine width directly on the image. The new formula combines different measured parameters to objectively quantify luster. It was designed to exhibit a higher correlation with visual perception along with a higher sensitivity. Results obtained with conventional formulae are compared on different hair tresses, treated and untreated. The new formula is found to be consistent for a whole range of hair colors, from light to dark.
J. Cosmet. Sci., 60, 111–123 (March/April 2009)
Synopsis
There is a need for both a better understanding of the technical drivers of shiny appearance in hair and for standard methods and measures of shine. To this end, we develop standard treatment methods for changing hair shine and examine a number of image‐based measurements of luster. Using psychophysical techniques to get a perceptual reference, we find that available technical measures are difficult to use when trying to quantify the small changes in shine associated with treatment.
J. Cosmet. Sci., 60, 323–336 (May/June 2009)
Accepted for publication October 21, 2008.
Compared with dark or brunette hair, blonde hair has different characteristic features of appearance such as bright shine with a soft tonal color. In this report, novel optical mechanisms of the characteristic blonde hair appearance are reported. Optical analyses of goniophotometric measurements were carried out to elucidate the mechanisms of strong reflections observed in blonde hairs. As a result, reflections with much higher intensity than those from the front surface of a fiber were confirmed to play important roles in the case of blonde hair fibers, and the intensities were found to vary with the cross-sectional shape of a fiber, the ellipticity (=minor axis/major axis). From light path simulation analyses, these strong reflections were verified to result from total reflection from the back surface of a fiber. Furthermore, since each hair fiber acts as a lens and/or a reflector, intricate reflection behaviors are suggested to occur as a consequence of the combination of light condensation and total reflection.
A new hair visual appearance measurement system called SAMBA from Bossa Nova Technologies (Venice, CA) has been employed to measure effects of cosmetic treatments on hair shine and surface smoothness of different types of hair samples. Experimental procedures for evaluations of shine value and surface cuticle angle of hair samples treated with rinse-off products (shampoo or/and conditioner) have been successfully established and applied. We demonstrated that hair spray and conditioner formulas containing PPG-3 benzyl ether myristate (PBEM) (1) showed great performance on shine enhancement for hairs with light and medium colors. Instrumental measurement of shine values was also conducted to compare different commercial shampoo and conditioner products. This study showed reliable utility of SAMBA system and demonstrated the shine enhancement of PBEM in hair care.
The adsorption of tributylphenol ethylene oxide isomers containing various lengths of ethylene oxide chain and positional isomers of tributylphenol on a riverine sediment was studied by thin-layer chromatography combined with high-performance liquid chromatography. The adsorption capacity of the sediment was compared with that of silica, alumina and diatomaceous earth. It was established that the adsorption capacity of the riverine sediment is similar to that of silica. The adsorption of surfactants on the sediment surface is not selective. Neither the length of the ethylene oxide chain nor the position of the butyl substituents on the phenol ring influence significantly the adsorption.
This paper presents three quantitative methods to examine gloss, opacity, and friction of cationic polymers. The adsorption of cationic polymers onto hair and skin can be regarded as a thin film coating. Therefore, optical and frictional properties of polymer films are of significant relevance to the applications of cationic polymers in hair care products. Such properties reflect the desirable hair condition attributes consumers seek in shampoo and conditioner products. Using these test methods, polyquaternium-10 and cationic guar samples of varying molecular weight and cationic substitution were compared. The effect of an anionic surfactant, sodium dodecyl sulfate (SDS), on polymer film properties was also investigated. Neat guar hydroxypropyl trimonium chloride imparts less friction than polyquaternium-10 but dulls the substrate employed in this study. The optical data show that polyquaternium-10 provides greater film clarity and gloss than cationic guars. In the presence of SDS, polyquaternium-10 also displays similar or lower friction than cationic guar. The comparative optical and frictional results are in good agreement with the visual assessment of the cationic polymer films. These results clearly demonstrate that polyquaternium-10 exhibits superior film properties in the forms of both neat polymer and polymer/surfactant complex. In addition, microscopic techniques such as scanning electron microscopy (SEM) and atomic force microscopy (AFM) provide powerful explanations for the differences noted between the two popular classes of cationic polymers. The test methods described in this paper can be utilized to differentiate the upper performance potential of cationic polymers. These objective and standardized test methods derived from the coatings industry are not affected by the variability of hair or the formulation complexity of end products. They can be useful tools in the product development process in quickly screening the relative performance of different polymers.
The consumer may repeatedly over the day apply intensive grooming procedures to maintain and improve hair appearance. Among these, brushing and combing are responsible for changes if not damage to the hair fiber surface. Beneficial or unfavorable changes to the hair surface may furthermore result from any cosmetic treatment. The analysis of laser-light reflection and scattering of human hair fibers is a direct, quick, and non-destructive method to monitor such surface changes. The application of a laser-based, multichannel goniophotometer is described, by which this analysis is based on the determination of the complete angular distribution of reflected light within a sub-second time interval. Systematic investigations of hairs differing in ethnic origin and color show that the goniophotometric curves can be analyzed by assuming three fractions of reflected light, namely, specularly, diffusely, and internally reflected light. Prominent effects are related to changes of the relative intensities of the different light fractions with hair color. The angular intensity distribution for each of the light fractions is well described by a Gaussian distribution. The angular positions of the peaks and their widths are analyzed. From the systematic shift of the intensity peak for specularly reflected light from its expectation angle, the tilt angle of the cuticle cells on the hair fiber surface is determined. All results are discussed with respect to changes along the hair length and for color differences.
Image analysis has been employed to measure the luster of hair simulated by light reflected from a curved hair tress. Hair samples (up to four) were mounted side-by-side in a special sample holder in the form of a cylinder and illuminated by a uniform beam of white light. Digital images of hair tresses were captured with a high-resolution camera and were analyzed by scanning across highlighted and dark areas of the resultant image using image analysis software with developed macros. Plots, similar to goniophotometric scattering curves, were used to calculate luster values according to previously published work by Nickerson, Stamm, and Reich-Robbins. Both the Stamm and Reich-Robbins approaches were found to give similar results, while the Nickerson gloss parameter exhibited less sensitivity to hair modification with cosmetic ingredients. The procedure was employed to assess the luster of natural white, light blonde, light brown, medium brown, and dark brown hair, and revealed an increase in luster indices in proportion to an increase in fiber pigmentation. Cosmetic oils such as phenyl trimethicone, amodimethicone, and castor oil were also found to increase the luster of hair as a result of the change in contrast between specular and diffuse reflection. Styling resins such as butyl ester of PVM/MA copolymer, vinyl caprolactam/PVP/dimethylaminoethyl methacrylate copolymer, and isobutylene/ethylmaleimide/hydroxyethylmaleimide copolymer were shown to increase hair gloss by a similar mechanism, as evidenced by calculated higher values of the Stamm and Reich-Robbins luster parameters. An effect of hair dulling by deposition of micronized ZnO at various concentrations, as well as by synthetic sebum, is also discussed.
One of the most desirable hair attributes to consumers, irrespective of ethnic background, is hair shine. The light reflected from a fiber has two components, specular and diffuse. The specular fraction of reflected light from the front surface of the fiber is generally recognized as a contributor to high luster. The distinction between specular and diffuse reflection is, however, not always clearly defined. In this study an attempt has been made to differentiate between specular and diffuse reflectance by analyzing mathematically goniophotometric curves of light reflected from unaltered single hair fibers from European, African, and Asian ethnic groups. The effect of macroscopic characteristics of the hair fibers, such as fiber diameter, cross-sectional shape, and curvature on luster is demonstrated. Results indicate that broadening of the specular peak reduces luster values, and is related to these characteristics. Thus, specular peak broadening is one of the important features to take into account when evaluating luster. Therefore, a new method for luster evaluation from goniophotometric curves is proposed. Additionally, we present the general model for light scattering, showing how scattering by surface roughness of different origin and magnitudes, and the scattering and absorption processes by the hair's interior, affect the position of the specular reflectance peak and its broadening.
The effect of color on instrumentally evaluated luster of hair dyed to different colors and depths of shades is studied. For natural hair colors, such as blond, brown, and black, the increase in luster with increasing color is associated with a decrease in diffusely scattered light as a result of light absorption by melanin granules. On dyed hair the interpretation of data from a goniophotometer (GP) is more complicated. Using the colors covering the extremes and middle of the visible spectrum, our results demonstrate how dye composition (single or multicomponent), concentration, and penetration depth into the fiber affect the absorptive and scattering processes within the hair fiber to impact luster. Finally, we make an attempt to study the effect of hair color on subjective evaluation of luster. An equation for perceived luster, taking into account the spectral sensitivity of the human eye is derived. Theoretical considerations show that the luster of hair of different colors is perceived differently by the human eye.
In this work we have explored capillary adhesion between hair fibers treated with different types of oils. With coconut, olive, and sunflower oils the capillary adhesion was found to decrease with time, but not with mineral oil. Application of heat reduced the capillary adhesion further for coconut and sunflower oils. Again, this was not observed with mineral oil. Based on an earlier study, where coconut oil was found to penetrate hair while mineral oil was unable to do so, it was hypothesized that the reduction in capillary adhesion resulted from the penetration of oil into the fiber, leaving a thinner oil film on the surface. Such a reduction in capillary adhesion can be explained by changes in Laplace pressure and in the areas of liquid bridges formed between the fibers. The thinning of oil films on the surface of hair has been confirmed independently by goniophotometric measurements on single hair fibers treated with coconut, sunflower, and mineral oils. Thick films of oil (thicker than approximately 0.5 microm) are known to mask the scale structure. As the oil is absorbed into the hair, the film thins with time and application of heat, and the scale structure reappears. This change can be conveniently determined by measuring the scale angle, using the well established goniophotometric protocol. The agreement between the two methods supports the concept that the reduction in capillary adhesion between hair fibers is most likely due to thinning of oil films by absorption of oil into the hair.
This paper reviews the current knowledge about human hair photodamage and the photodegradation mechanisms proposed in the literature. It is shown that there are still a number of questions without answer regarding this issue. For example, a better understanding of the hair structural changes caused by different radiation wavelengths is still lacking. We also find controversies about the effects of sun exposure on different hair types. Explanations to these questions are frequently sustained on the amount and type of melanin of each hair, but factors such as the absence of knowledge of melanin structure and of established methodologies to use in human hair studies make it difficult to reach a general agreement on these issues.
Hair luster has long been a key objective for consumers in the hair care market and many researchers have sought to quantitate the luster of hair fibers or tresses. Recently, a fast polarimetric video camera called SAMBA with a high polarization contrast was introduced that can effectively separate specular and diffuse light. Instrumental measurement of shine using SAMBA was conducted to quantitate the luster on phenyl trimethicone-treated hair tresses. We confirmed with atomic force microscopy that phenyl trimethicone's luster-enhancing effect was related to its reduction of hair surface. Panel tests by 15 untrained panelists were carried out to determine whether their assessment corresponded with instrumental results. The instrumental data showed an excellent correlation with subjective assessments from the 15 panelists. This study shows that SAMBA has utility as an instrumental technique for hair luster evaluation and is in good agreement with consumers' subjective evaluation of luster.
With the use of a greater variety of metals and methods of finishing them, an increasing need to measure metallic appearance has developed in the automotive industry. A simple and easy to operate instrument has been designed to measure the geometric characteristics of reflectance related to metallic appearance. These are specular reflectance, distinctness of image, haze, and diffuseness. A series of selected aluminum and stainless steel specimens has been used to test the performance of the new instrument and of older devices with which it has been compared. Functionally, the new instrument combines features of the Distinctness of Reflected Image (DORI) meter designed by Tingle, and the abridged goniophotometer designed by Tingle and George. The design and operation of the new instrument have been simplified by use of multiple receptor apertures with optical fiber light collectors. The measurement of a wide range of metal appearance characteristic has thus been achieved with mechanical and electrical circuit simplicity.
A laboratory instrument for the measurement of “delustre” in woven filament fabrics is described. The method of measurement is very sensitive and detects differences in lustre not easily visible by eye. It is convenient for use in mills for purposes of control.
Human hair consists of proteins, lipids, water, trace elements and pigments. The composition of the first four of these components is the focus of this Chapter. About two decades ago the emphasis on the proteins of hair was on its amino acid constituents which provided important information on the relative amounts of different functional groups in different types of hair and in different regions of the fiber. However, as a result of advances in the characterization and classification of the different proteins and genes of keratins and keratin associated proteins the focus today is on the proteins themselves. Several important new contributions to the composition of the surface layers of hair and the proteins of the cell membrane complex have been and are continuing and therefore are summarized in this Chapter. The current state of changes in the amino acids, proteins and lipids of hair by morphological region (including KAP and keratin proteins and where they reside), chemical and sunlight damage, diet, puberty and menopause, and other factors have been and are being made and are summarized here. An expanded section on metals in hair, where in the fiber these metals reside and the functional groups that they bind to and their effects on hair chemistry, toxicity and disorders are included.
Synopsis By using a GONIOPHOTOMETER and linearly polarized parallel white light incident obliquely on planar arrays of parallel oriented taut HAIR FIBERS, the light scattered and specularly reflected from the fibers has been recorded as a function of the angle of observation and direction of polarization in the exit beam. It can be categorized as being: (a) reflected from the air-cuticle interfaces on the near side (white light), from the cuticle-air interfaces on the far side (colored light), and from an interface probably consisting of a discon-tinous wedge-shaped sheath of air parallel to the axis of the fiber; or (b) scattered from optical imperfections which are principally on the surfaces of the fibers. Specular reflection from the front air-cuticle interfaces is independent of hair color and permits an evaluation of O (-3ø), the angle of inclination of the scales to the axis of the fiber.
Cotton and synthetic fibers were studied analytically and experimentally to determine the basic cause of luster in fibrous materials. The analytic technique used provided a mathematical description of the interaction of light with a nearly ideal fiber, namely, glass. An instrument was constructed to measure the angle and intensity of light scattered from single fibers. A number of fibers were investigated in this way. The ideal glass fiber gave experimental data which correlated with those from the analysis. By the use of polarized light it was possible to measure the coherency of the scattering process, which was found to be a measure of the luster of the fibers.
Under suitable experimental conditions, it was shown that surface reflection from a fiber is the source of the luster quality and that a small degree of surface roughness is very effective in decreasing the luster. It is not known exactly what magnitude of surface discontinuity is most responsible for loss of luster; however, it is quite possible that ways may be found to decrease these discontinuities and so increase the luster of cotton to any degree desired.
A single-answer, direct-reading instrument especially adapted for measuring luster of raw cotton and grey and mercerized yarns has been developed. It includes a special sample clamp, and a turret-top holder for the instrument. The sample is illuminated at 45° and measured at 0° and 45°. By means of a special circuit, the ratio of these two measurements may be read directly from an automatically indicating scale in terms of "per cent luster. Samples are easily and quickly prepared from .yarn skeins on special holders, and a similar but narrower holder is used for measuring combed fibers from pinches of blended raw stock samples. Results are related to goniophotometric measurements made for several conditions of illumination. Luster, sample preparation and holder, the instrument, calibration, and luster results for the USDA's Standardized Variety Series of cottons are discussed and summarized. The instrument is an adapta tion of a simplified all-purpose glossmeter under development by R. S. Hunter.
The optical properties of human hair were studied by photogoniometry. Starting from an optical model of hair, we developed a computerized method of decomposition of the goniophotometric curve. From our analysis we obtained structural parameters of the hair surface, average scale angle and cosmetic parameters like lustre and pigmentation. This method gave us new results in the following areas:
— the effects of bleaching on scale and internally reflected light;
— the study, from root to tip, of surface damage and hair pigmentation;
— the effects of stretching the hair on scale angle and lustre;
— the effects of sebum and dust on hair lustre.
L'étude des propriétés optiques du cheveu a été réalisée par Photogoniométrie. A partir d'un modèle optique du cheveu, nous avons développé une méthode de décomposition, par ordinateur, de la courbe photogoniométrique. Nous obtenons ainsi des paramètres structuraux de la surface des cheveux et I'angle moyen des ecailles et sa répartition ainsi que des paramètres cosmétiques, la brillance et la pigmentation.
L'application de cette méthode a permis d'obtenir des résultats originaux dans les domaines suivants;
— influence d'une décoloration sur l'angle des écailles et sur la réémission de la lumière;
— suivi, tout au long des fibres, des altérations de la surface et de la pigmentation;
— influence du sébum et de la pollution sur la brillance des cheveux.
Synopsis
An automated goniophotometer has been built to investigate the scattering of light by different types of singly mounted human hair fibres using white light and laser illumination. The effects that varying hair colour and treatment (gold coating, ultraviolet irradiation and dyeing) have on the specular reflectance and on the half‐peak‐height width (ω) have been studied. The polarization of light has been used to discriminate between light reflected from the front surface and light scattered internally by the hair. It has been found that the analysis of results from individual hair fibres has been useful in understanding the light scattering mechanisms which occur in human hair.
The optical properties of human hair. II. The luster of hair fibers
- R F Stature
- M L Garcia
- J J Fuchs
R. F. Stature, M. L. Garcia, and J. J. Fuchs, The optical properties of human hair. II. The luster of
hair fibers,.].
- Soc
Soc. Cosmet. Chem., 28, 601-609 (1977).