A Personal Computer (PC) adjusts a color of an image received from a digital camera to produce an estimated reflectance spectrum and/or to convert the color to a new color space. First, an input compensation transform is generated, e.g. based on a Macbeth color chart in the image, to compensate for the sensitivity of the camera used to generate the image to different wavelengths of light and the illumination spectrum incident on an object of interest to which the image relates. In order to estimate the reflectance spectrum, a reflectance spectrum estimation transform is then generated by the PC. In order to convert the color of the image to the new color space, a color space conversion transform is generated by the PC. Both the reflectance spectrum estimation transform and the color space conversion transform are based on the input compensation transform and reference reflectance spectra stored in a reference reflectance spectra database.