Legislation requires that potable water must be almost colourless and to achieve this water from rivers, reservoirs and reclaimed sources is put through a thorough purification procedure before being distributed for consumption.

For over one hundred years the accepted method for checking that the colour is within acceptable limits is by using dilutions of the platinum as a colour standard. This can be carried out visually or spectophometrically.

Scales & Values

Grading techniques are widely used to assess product colour by comparison with a representative series of fixed colour standards.

For many product types, a characteristic set of standards was agreed and adopted to aid colour control and the communication of colour specifications; the result is a selection of traditional colour grading scales that have been adopted as industry standards and are still in common use today.