FAQ: “…. the schema of the principle of measuring shows other way of light (source of light -> sample -> sphere -> detector) than our ColorQuest (source of light -> sphere -> sample -> detector). Please can you explain me difference between both construction? difference between both results of measuring?”
directional
FAQ: “Straight from the LSXE Pro-forma, the LabScan XE sample ports are described as:
Port Insert, 3-mm illuminated area; 5-mm measured area
Port Insert, 6-mm illuminated area; 10-mm measured area
Port Insert, 13-mm illuminated area; 17-mm measured area
Port Insert, 25-mm illuminated area; 30-mm measured area
Port Insert, 44-mm illuminated area; 50-mm measured area
I always thought that the measured area was smaller than the illuminated area. Have the illuminated/measured area in the Pro-forma been transposed? Seems like it!”
The geometry of an instrument is the relative position of the light source, sample plane and detector, and is one of the 6 key parameters that define a color measurement. There are two general categories of instrument geometries – directional 45°/0°(or 45°/0°) and diffuse d/8° sphere.
To tell the difference between directional and diffuse instrument geometries, look in the port. If the inside is black, when the lights are on, the instrument has a CIE directional 45°/0°(or 45°/0°) geometry. If the inside is white, then it is a CIE diffuse d/8° sphere geometry instrument.
While both geometries can be used for color measurement, it is best to measure some samples with a directional 45°/0° geometry instrument and others with diffuse d/8° sphere. More information in our Application Notes at AN 1033.00 Color versus Appearance.