Monpeurt C, Cinotti E, Razafindrakoto J, Rubegni P, Fimiani M, Perrot J L, Hebert M
Institut d'Optique Graduate School Rhône-Alpes, Saint-Etienne, 42000, France.
Department of Medical, Surgical and Neurological Science, Dermatology Section, University of Siena, S.Maria alle Scotte Hospital, Viale Bracci, 16, 53100, Siena, Italy.
Int J Cosmet Sci. 2018 Feb;40(1):75-80. doi: 10.1111/ics.12436. Epub 2017 Nov 14.
The colour of a nail polish varies according to the nail on which it is applied. The objective of this study was to predict the colour of the nail polish on a given nail and to study how the colour varies depending on the nail polish thickness.
Six nail polishes were applied in one, two and three layers on the nails of one subject, thus forming eighteen samples. The spectral reflectances of the eighteen nail polishes applied on the nails with different thicknesses were obtained by spectrophotometry. The spectral reflectances of the nails without polish were also measured using the same technique. The thicknesses of nail polishes were measured by high-definition optical coherence tomography (HD-OCT). Then, to determine the physical parameters of the nail polish itself, we applied the six nail polishes on an opacity drawdown chart and we measured the spectral reflectance and the thickness of each patch using spectrophotometry and HD-OCT, respectively. The Kubelka-Munk theory was used to get the predicted spectral reflectance of the nail polish applied on the nail according to the polish thickness by knowing the parameter of the polish itself and the spectral reflectance of the nail. The predicted spectral reflectances were finally compared with those measured directly on the nails.
The predicted spectral reflectances were rather close to measured ones. Consequently, knowing the colour of the nail without polish and the optical parameters of the nail polish itself, we can estimate the colour of the nail polish applied on the nail depending on its thickness.
Our study showed that the Kubelka-Munk theory can be used to predict the nail polish colour. The ability to predict the real colour of a nail polish applied on a nail could help a nail polish manufacturer to improve his polish formulae in order to obtain a precise colour.
指甲油涂在不同指甲上颜色会有所不同。本研究的目的是预测涂在特定指甲上的指甲油颜色，并研究颜色如何随指甲油厚度变化。
在一名受试者的指甲上分别涂一层、两层和三层六种指甲油，从而形成18个样本。通过分光光度法获得涂在不同厚度指甲上的这18种指甲油的光谱反射率。也使用相同技术测量未涂指甲油的指甲的光谱反射率。通过高分辨率光学相干断层扫描（HD - OCT）测量指甲油的厚度。然后，为了确定指甲油本身的物理参数，我们将六种指甲油涂在不透明度递减图表上，并分别使用分光光度法和HD - OCT测量每个色块的光谱反射率和厚度。根据指甲油本身的参数和指甲的光谱反射率，利用库贝尔卡 - 蒙克理论通过指甲油厚度来获得涂在指甲上的指甲油的预测光谱反射率。最后将预测的光谱反射率与直接在指甲上测量的结果进行比较。
预测的光谱反射率与测量值相当接近。因此，在知道未涂指甲油的指甲颜色和指甲油本身的光学参数的情况下，我们可以根据指甲油厚度估计涂在指甲上的指甲油颜色。
我们的研究表明库贝尔卡 - 蒙克理论可用于预测指甲油颜色。预测涂在指甲上的指甲油实际颜色的能力有助于指甲油制造商改进其指甲油配方以获得精确的颜色。
