Spectra of the reflectance of a Washington State Golden Delicious apple

The two spectra shown in the above chart are of the surface reflectance of the apple whose image is shown above. The two spectra were take using an Ocean Optics S1000 spectrometer, Illumination was by sunlight, referenced to a CDH-50 standard white (of Albrillon). Sunlight referenced to the standard white was quite satisfactory for these reflectance measurements.

The spectrum shown in red color is the reflectance from a more "rosy-yellow" section on the apple (1). The spectrum shown in orange is the reflectance from a slightly sun-burnt portion at the top of the apple (2). The spectra shows the increased reflectance in the yellow stimuli region (550 nm - 600 nm) of the middle portion of the apple and a lesser overall reflectance toward the top, where a few sun-burn spots are located.