Dyes

I’ve just finished my summer reading book, Ken Follett’s novel World Without End. If you haven’t read it, I would thoroughly recommend it, although it is the second book of a trilogy (book 1 is called The Pillars of the Earth). The book I sent in the thirteenth century in the fictional city of Kingsbridge in the UK (although there is a Kingsbridge in the UK, the Kingsbridge in the book is not this town) and revolves around the Black Death. Without giving too much away about the story, and focusing on the inspiration for this blog post, one of books heroines learns how to dye cloth red which makes Kingsbridge famous throughout the UK and Europe (and her very rich). She learns to use Alum as a mordant and then the root of the Madder plant to dye cloth a striking red colour.

This did get me thinking, especially with regards to dyeing cloth and possible IAs, but maybe I’m getting ahead of myself a bit.

Firstly, what is a mordant? It’s not part of the chemistry course although you may have come across it pre-IB. A mordant will fix a dye to the cloth. Without the mordant, the dye would wash away over time. The mordant helps the cloth retain the colour. A mordant is also a metal containing compound (Alum or aluminium sulfate has already been mentioned).

A little bit of research took me to http://www.allnaturaldyeing.com/ which contains a wealth of information. It also turns out that the mordant influences the colour of the fixed dye. For example, mordants containing iron will dull down a colour where copper-containing mordants will favour green colours.

It is possible to use lots of different dyes. The roots of the Madder plant will give a red colour and the older the plant the deeper the colour of red. But plenty of other plants will give slightly different reds, for example, beetroot or hibiscus flowers.

The Madder plant
Source: H. Zell , Creative Commons (CC BY-SA 3.0), via Wikimedia Commons

How does this tie in with an IA? Well, could you use different plants to produce different shades of red (not sure what the research question would be here) or could you use different mordants and evaluate the effect of the colour whilst using the same plant (not sure how you would quantitatively evaluate your results though) or could you just look at the effect of different concentrations of dye on the colour of the cloth? With a little imagination, I am sure there are other variables you could decide to investigate.

Do you have any experience of dyes or mordants? If you do, please share these experiences with us below. I would love to read about them.