The traditional craft of natural dyeing os alive and well in the Orkney islands

It's been 40 years since Woodstock, and the flower children are grannies, but the splodged homemade tie-dyed T-shirts they wore with pride seem to have become a rock festival tradition.

Every year you can spot tie-dyed T-shirts in the crowds at T in the Park. You'll see them on the streets of Edinburgh during the Festival and there's always somebody selling them at Glastonbury.

Craft-based websites seem to have got in on the act, and purists are now decrying cheap synthetic dyes and urging people to try their hand at doing even messier things with plant-based natural dyes.

Denise Dupres, who combines farming with her Orkney-based craft-workshop activities at the Woolshed in Evie, is a natural-dye specialist who produces an array of hand-dyed tops, fleeces, rugs and teddy bears. She's delighted to see a rise in interest in the art of natural dyeing.

She says: "For many years there's been a subculture there that hasn't been widely publicised, but it's never been difficult to get natural dyes. Firms will send ready-prepared extracts, but because synthetic dyes were cheaper they were much more generally used."

Going back to nature for dyeing wool is something she finds both fascinating and challenging.

"Natural dyes are hugely complex and need a lot of careful research. They're very difficult to colour match because one batch might be from plants grown in shade, and another from the same type of plants grown in sunlight. The end product will be different, as it will if the plants are grown in a different type of soil," she adds.

In days gone by, people in rural areas were well versed in the art of home dyeing, and a great deal of one-upmanship was practised in the different communities, with secret recipes being handed down from family to family.

Denise explains: "If you knew what you were doing, anything and everything could be used to produce a dye - berries, meadowsweet, onion skins, brambles, dog rose or dockans."

The dyes could be set using a mordant, based on various salts of chromium, copper, iron or tin, but some natural shades relied on bacterial or yeast fermentation to remove the oxygen. Urine vats were the cheapest way and the staler the better, so collection barrels were kept at the end of the house, and everybody added their quota.

One of the most commonly used dye sources was crottle, a type of lichen found growing on rocks. Crottle was the base for a substantive dye, says Denise, that didn't require a mordant. Such dyes spent around 28 days fermenting in a pot of urine kept at a constantly warm temperature at the back of the stove. Once ready for use it was mixed with chalk and rolled into balls for storage.

Harris tweed was coloured using this dye, and as such was renowned for its distinctive odour.

The occupants of present-day kitchens - however keen on natural dyeing - would not be prepared to tolerate a month of pungent fermentation processing, and so less offensive methods of dye setting are now used. Denise will be part of a group demonstrating natural dyeing methods in Orkney on Tuesday which will include a trip to the island of Graemsay to collect and boil up natural dyes. It's part of the community's summer events calendar and is aimed at rediscovering old skills that have fallen out of common usage.

To find out more about the event organised by Scapa Flow Landscape Partnership scheme, tel: [phone] extension 2882.

• This article was first published in The Scotsman, Saturday August 14, 2010