IMPROVEMENTS RELATING TO COLOUR MEASUREMENT

摘要

A colour referencing system is provided whereby a process colour is first defined in terms of percentage levels of a number of base colours to create a standard reference, an ink mixture is experimentally defined for a flat colour which corresponds in appearance to the process colour and the CIELAB or other colour difference equation value is determined by conventional means for that matched colour. Such a system is only possible if the process colour reference standard can be repeated without error. The illustration of the process colours in relation to their standard reference is therefore ideally achieved by the system as is defined in European Patent Number 0119836. It is then possible to start from a flat colour produced by single ink printing and reproduce this exactly as a process colour by a predetermined combination of four colours using particular screened percentage values.