The present disclosure is directed to a method for producing color spectral data of an article illuminated with lights emitted from one or more light emitting units, such as light emitting diodes (LEDs). The method is useful for obtaining accurate color spectral data of the article and for matching the color data produced from another color measuring instrument. The method is particularly useful for obtaining color spectral data using light emitting diodes as light source for color measurement. This disclosure is also directed to a color measuring system using the method disclosed therein.