For both quaternary mixes, there is potential for applying the DCI method, although the relationship between colour and salt concentration was not as strong as P/S. The reason for this is partially due to two of the components having very similar colours, which the DCI method could potentially not distinguish. However, it could be argued
that in multi-component mixes, such as quaternary mixes, the influence of two components having very similar colours could be partly overcome by the other components having different colours, provided that they do not have an inherent segregation tendency. Consequently, the DCI method may still be effective even if some of the components have very similar colours