Cornell Box House Paints
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[Rendering] The full hemispherical BRDF of spray-painted latex blue paint, Pratt & Lambert, Vapex Interior Wall Base 1, Color #1243, Cal.III.

The incidence angles are 0°, 20°, 35°, 55°, 65°, 75°, and 85°. For each of these, there are 19x73 measurement angles across the hemisphere. Wavelengths span the visible range. Data are in MATLAB binary files.

  • paint.raw.mat contains the raw measurement data:
    • e.g. brdf00: BRDF values at 0 degrees incidence angle, for 65 wavelengths and 16 (or more) outgoing directions.
    • e.g. phi00: the 16 corresponding outgoing azimuthal angles.
    • e.g. theta00: the 16 corresponding outgoing polar angles.
    • wavelengths: the 65 corresponding wavelengths (note that data below 450nm are very noisy).
  • paint.clean.mat contains the data after reorganisation, with interpolation of missing values:
    • e.g. brdf00_450: 19x73 BRDF values at 0 degrees incidence angle and a wavelength of 450nm.
    • phi: the 19x73 corresponding outgoing azimuthal angles.
    • theta: the 19x73 corresponding outgoing polar angles.
  • paint.reformat.mat contains the same data as paint.raw.mat, but reorganized to match the format of all our other MATLAB files:
    • dir_in: the 1255 incoming direction vectors (with the z-axis of the coordinate system aligned along the normal).
    • dir_out: the 1255 outgoing direction vectors.
    • fr: the 1255 BRDF values at 65.
    • wavelength: 65 wavelengths corresponding to fr
The following plots give an impression of the behavior for a few incidence angles at a few wavelengths between 450 and 650nm, in the plane of incidence only:

[Graph]0° - largely diffuse, with a small retro-reflective bump. The lobes are larger for short wavelengths (blue, cyan,... curves), because the paint is blue.
[Graph]35° - the bump on the left is a retro-reflective bump.
[Graph]55° - again, the bump is a retro-reflective bump. The forward scattering on the right becomes apparent, especially for long wavelengths, for which there is less subsurface scattering.
[Graph]75° zoomed out. Note the strong forward scattering. The directional-diffuse lobes are approximately equally sized for different wavelengths, yielding colorless highlights.

Bristol Data

We measured a set of five samples provided by Ann McNamara of Bristol University. These were flat interior house paint in neutral colors ranging from black to white. The BRDF of each sample was measured at 1502 combinations of incident and exitant angles. The incident angles were 10°, 20°, ... 80°. The exitant directions are distributed uniformly over the hemisphere. The BRDF measurements were made at 550nm; we also include the directional-hemispherical (diffuse) reflectance as a function of wavelength, as measured by our Optronics OL-750 instrument from 300 to 700nm. The MATLAB file for each sample contains the following variables:
  • dir_in: the 1502 incoming direction vectors (with the z-axis of the coordinate system aligned along the normal).
  • dir_out: the 1502 outgoing direction vectors.
  • fr: the 1502 BRDF values at 550nm.
  • data: the diffuse reflectance at 41 wavelengths.
  • wavelength: 41 wavelengths corresponding to data

Sample MATLAB file ASTM file Diffuse reflectance spectrum
Black bristol1.mat bristol1.astm bristol1.spc
Dark gray bristol2.mat bristol2.astm bristol2.spc
Medium gray bristol3.mat bristol3.astm bristol3.spc
Light gray bristol4.mat bristol4.astm bristol4.spc
White bristol5.mat bristol5.astm bristol5.spc

Added paint.reformat.mat: data reorganized into format similar to other datasets April 2, 2001
Added Bristol data January 11, 2001
Separated into its own directory January 11, 2001

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Last updated 04/02/01 PCG www Home