Hydrophilic-lipophilic balance (hlb):

An expressions of the relative attraction of an emulsifier for water and oil, determined largely by the chemical composition and ionization characteristics of a given emulsifier.

The hlb of an emulsifier is not directly related to solubilit5y, but it determines the type of emulsion that tends to be formed.

It is an indication of the behavioral characteristics and not an indication of emulsifier efficiency.