The difference between the weights of salt used in the more dilute water plus salt solution is so small that if complete separation at one salt concentration is not achieved due to small variations in properties of different batches of cellulose (density, polarity, etc.), then the next more or less concentrated solution should be used, depending on whether the dyes move too slowly or rapidly (with reference to each other) to separate. The dyes were used in relatively dilute solution in order to correspond to concentrations most frequently encountered in commercial use.