Colour measurement of toy car at UCL
The colour of the toy car was measured by a spectrophotometer, the 'eye-one' from Gretag-Macbeth. The instrument uses a 45/0 illumination geometry, and averages the reflectance over a circular 4mm aperture. It gives the reflectance factor (fraction of light reflected by the surface) at each wavelength of the visible spectrum, in steps of 10nm. The data was imported into an Excel spreadsheet and plotted.
See the attached images for an image of the graph, and the read outs.
The graph shows:
1) White paint from the hood (bonnet) of the replica car. The reflectance spectrum rises to nearly 90%, but is lower at short wavelengths which accounts for its cream colour.
2) Grey metal from the trunk (boot) of the real car. The reflectance factor is very nearly constant between 15% and 18% across the entire spectrum, but falls slightly at long wavelengths which accounts for its slightly blue-green tinge.
3) Red paint from the dashboard of the real car. The reflectance factor is low (less than 5%) for the short and medium wavelengths, but rises to 40% at long wavelengths.