Depending on the process used, Merino can easily dye into a wide range of colours. Proteins in the core of the fibre can be reactive, absorbing and combining with the dye so that it actually becomes part of the fibre.

Merino dyestuffs

Dyes employed in the colouration of Merino fabrics are generally supplied as powders, granules or in liquid form.  They are soluble in water, and have been designed to have a strong affinity for the protein of the Merino fibre.

Classes of merino dyestuffs

In general, Merino dyes are classified according to their chemical type and method of application.  The main classes of dyes currently used for the dyeing of Merino fabrics are:

• Acid dyes,
• Metal complex dyes (pre-metallised dyes)
• Chrome dyes
• Reactive dyes.

Inappropriate dyestuffs for Merino

Other classes of dyestuffs, such as direct dyes, vat dyes, sulphur dyes, basic dyes and disperse dyes are not suitable for Merino for a variety of reasons including poor colourfastness to washing and light. The highly alkaline reductive dyebaths used to apply vat and sulphur dyes to cotton would severely damage Merino fibres.

Colourfastness of Merino dyestuffs

The degree of colourfastness varies with the various Merino dye classes, as do other factors including colour range and cost. Acid-levelling dyes are cheap and capable of producing bright pastels but have poor wash fastness. Reactive dyes, on the other hand, while being more expensive, are capable of delivering the same colours but with excellent colourfastness.

Summary

Proteins in the core of the wool fibre absorb dyestuffs, providing Merino with a broad palette of rich, subtle and unique colours.

Readings

• Check out the Society of Dyers and Colourists (UK) Web Site at http://www.sdc.org.uk/ for some interesting examples of the psychology of colour, news and publications under “Colour Click” and links to other web sites.
• A glossary of dyes and dyeing terms is available at:  Click here

References

• Lewis, D.M., 1992, Wool dyeing, Society of Dyers and Colourists, ISBN 0 901956 53 8
• Parton, K., 2002, Practical wool dyeing, Chapter 8 in Merino: Science and Technology, editors W.S. Simpson and G.H. Crawshaw, The Textile Institute / Woodhead Publishing Ltd / CRC Press, ISBN 1 85573 574 1.

All figures and tables courtesy of CSIRO unless otherwise noted.