Spectral reflectance scale method and apparatus

摘要: Methods and apparatus for measuring the reflectance in a visible spectral wavelength band by visual comparison of surface viewed through filter with set reference areas are described. An appropriate reflecting useful estimating skin pigmentation, corresponding sun sensivity exposure time tolerance. Tables included solar erythemal radiation environment different locations times year use determining sunlight Also methods to data along local ultraviolet index determine tolerance included. In addition, ensure sufficient previtamin D generation techniques reduce risk cancer. The combination gray scale measurement results low cost device other meters instruments making affordable many persons.