Honey colour is measured on a "Pfund Grader". The scale for this is called the "Pfund" Scale and is measured in millimetres. The scale is actually a metric ruler measuring the point along a calibrated amber glass wedge where the sample (placed in a glass wedge shaped trough) matches the amber wedge. The scale starts at 0mm (colourless) and finishes at 140mm (black). Some common terms describing the colour of honey actually have specific ranges on the Pfund Scale. These also vary slightly from country to country with the USA, Canada and Australia all having slight variations. The US scale is :

0-8mm Water White

Up to 17 mm Extra White

Up to 34 mm White

Up to 50 mm Extra Light Amber

Up to 85 mm Light Amber

Up to 114 mm Amber

Over 114 mm Dark

In many cases we have over 1,000 samples on file for a particular honey type and are able to compare the average colour plus Standard Deviation of the colour with that of a sample under analysis.