Tolerance setting

The manufacture of most coloured goods involves at some stage a decision as to whether the product will be acceptable against the required standard for the colour. This tolerance may have been set in a variety of ways; perhaps by long customer usage, perhaps by a committee of interested parties or just by 'they didn't complain last time when it was worse than this'! Whatever the method, problems are encountered when human decisions are made concerning colour tolerances. The variability of the decisions that are made does not generally affect the batches of material that are very close to the required standard nor those that are very far off in terms of the tolerance already prescribed. These are simple pass or fail cases. It is in the large number of cases which are borderline that problems arise. A wrong decision here can cost money. A batch unnecessarily failed is certainly poor economics and one that is passed but is returned by the customer besides losing money causes delivery delays, Studies of thes sorts of decisions have shown that 20% of them are in error. This rate of error can be reduced to 2% if colorimetric methods are correctly applied.