Series 52 is the original Lovibond® Brown colour scale now currently used for the colour grading of whisky, honey and similarly coloured liquids or syrups.
The standard version of this scale includes a series of 23 amber/brown glasses although other values are also available.
EBC Colour has largely superseded it for the grading of beers in Europe but it is still used for beers in the US and for whiskies. Is is sometimes referred to as degrees Lovibond® in the US brewing industry.
It is also suitable for sugars solutions and syrups.