Metal finishing Q&As since 1989

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Different angles of measurement and the possible interrelationship

A multiangle measures the reflection at more than one angle of illumination or observation.
What does each of reflection angles represent ?
For e.g,, When an effect pigment embedded dry film coated on a substrate is measured at 20, 45, 75 & 110 degree illumination angles; my question is :
1. What does 20 deg. data represents ? 45 deg? 75 deg.? 110 deg.?
2. Is these any correlation between these angles so that the overall result can be represented by a single parameter ?

HARISH VENKATRAMANA PATWARDHAN
- Bangalore, KARNATAKA , INDIA
2006

A multi-angle spectrophotometer is used to measure the colour of metallic finishes. These colours differ depending on the angle they are viewed at. Example, face on red, at an angle blue. They are produced by using flaked aluminum or mica flakes. The orientation of the flakes determines the colour. The instrument will read the colour at each specific angle giving a result at each angle. These results can then be used for QC purposes. A regular spectrophotometer is useless as it sees the metallic as one homogeneous colour.

Ronald Zeeman
Coil Coating - Brampton, ON, Canada
2006