Shade passing : applications in the manufacturing of multi-component apparel with particular reference to colour matching

Abstract

In recent years, computer colour management systems have become increasingly important to the colour industry where techniques such as instrumental pass/fail analysis are widely used by manufacturers, buying offices etc. However, a matter of major concern remains the assessment of pass/fail on a single component. In the case of apparel comprising a multiple of components, the existing commercial instrumental pass/fail systems seems not suitable. The Polytechnic University is supported to implement the Teaching Company Scheme (TCS). Under the TCS, research project directly related to the needs of client company, Triumph International Overseas Ltd.(Hong Kong Branch), was undertaken under the supervision of an academic staff member. Referring to Triumph's practice, three equations chosen for study were CIELab 1976, CMC(2:1) and CIE94(2:1:1). Colour difference, ΔE, of 230 sample pairs with different textures was calculated using the above equations. Totally 33 experienced "shade passers", including Triumph's and external colour assessors, were invited to assess these sample sets and gave comments on them. The comments given should be a pass match, fail match or marginal pass match. The data collected were then analyzed statistically. The percentages of acceptance were plotted against various ΔE calculated with respect to its equation. The results show that equation CMC(2:1) has a better correlation than the other two equations. The tolerance block so developed based on the CMC(2:1) equation was verified by applying the tolerance to one of the suppliers of Triumph. The precision and performance of the tolerance block developed is fairly good and acceptable. In addition, analyzed data show that better correlation could also be attained by increasing the number of observers.