The Role of Instrumental Colour Control in the Optimization of Dyehouse Performance

Abstract

The paper describes the general techniques used and the results obtained in pilot plant and commercial dye‐house experiments carried out to demonstrate the potential of an inhouse spectrophotometer and minicomputer system in: high‐accuracy recipe prediction to produce bulk dyehouse recipes without laboratory check dyeing calculation of redye procedures to correct off‐shade bulk dyeing control of dyehouse pass/fail matching by instrumental methods preparation of recipe cards, druglines and cost information by computer methods.

Evolution of right‐first‐time dyeing production

“…This could be translated into bulk as an RFT dyeing. The J. P. Coats organisation developed the prediction program further, using non‐linear equations incorporated by McDonald in 1968 to accommodate the variations in dye uptake at different concentrations [64], so that the predicted recipe could be transferred into bulk and give within‐tolerance (RFT) dyeing without a preliminary laboratory check [21,65]. This organisation was also the first to utilise a feedback system developed by McDonald [66] in 1980 and later patented, whereby the results from previously successful predicted recipes were used to obtain predictions for new colours.…”

Has the SDC Journal catalysed changes in coloration technology?

“…Gailey [50] gave an appraisal of the application of automation to package dyeing, highlighting the factors that must be considered and reviewing the progress within the J P Coats organisation. At the 1975 Society symposium held in Nottingham, Noble [51] outlined the importance of automation and the benefits that could be obtained, Simmons [52] discussed the objectives required while the use of instrumental colour control to optimise dyehouse performance was discussed [53]. By 1976, Gailey confirmed [54] that the technical requirements, at least for package dyeing, for total automation had been fully developed and that the necessary hardware could be purchased off the shelf.…”

Industrial Pass/Fail Colour Matching. Part III‐Development of a Pass/Fail Formula for use with Instrumental Measurement of Colour Difference

“…Shortly after the introduction of a mini-computer based recipe prediction system into the dyehouse of J 81 P Coats (UK) Ltd [3], arrangements were made with the Dyehouse Manager that spectrophotometric measurements would be made of all colour matches carried out by him. Over the course of approximately two years, some 8454 pass/fail visual matches were carried out on 85 dtex x 3 staple spun polyester thread.…”

“…The plots indicate that the Lightness limits become wider as the Lightness of the standard is increased but they are not significantly affected by changes in Hue-angle of standard. A computer Simplex iteration program had been developed some years ago in J & P Coats Research Laboratories for other Colour Physics work to determine the constants in a two-constant curvilinear dye uptake equation [3]. The Lightness differences from the individual Hue-sector plots were therefore combined, and a similar analysis t o that described for the Metric Chroma differences was carried out to determine the limits of Lightness tolerance, Lt, a t different Lightness values of standard.…”