pigmented colorants: dependence on media and time - Cornell ...

Measurements were taken for each sample at six different periods of time. The
diffuse reflectance of the samples was measured directly after they were freshly
painted, after one day, after one week, after one month, after three months, and
six months after they were painted. From 21 <strong>pigmented</strong> mixtures and 8 different
binding media, there are 168 different samples. Each sample’s reflectance was
measured over the visible spectrum (350-700nm) in 10nm increments. Hence, there
are 36 wavelength-dependent reflectance values for each sample. Ultimately, each
sample was measured six times for a total of 1008 time-dependent reflectance
spectra (each of which contains the 36 wavelength-dependent reflectance values).
The samples were subjected to conditions similar to a less-traveled gallery. The
atmospheric conditions were fairly constant, as the samples were kept indoors.
The room temperature remained constant, at approximately 70 o F. Illumination in
the room was a combination of General Electric fluorescents Chroma 50 (which
has a continuous spectral distribution similar to that of daylight) and Deluxe
Specification Series 3500K (a tri-Phosphor lamp with very good color rendering
and efficacy). Illuminance on the samples was between 235-560 lux. After creation,
the samples remained face-up on a table, unless they were in the process of being
measured, and were never touched on the paint surface.
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