In the past, using dyes wasn't a problem for the environment, as they were made of natural products such as plants.
Now teachers and students at the Technological and Higher Education Institute of Hong Kong (THEi) have begun a project to make organic dyes from the dried plants used in Chinese medicine. They want to raise public awareness of the issue, and encourage people to save the Earth by wearing "green" clothes - those coloured with organic dyes.
Creating organic dyes is so easy, everyone could do it at home, using plants bought at Chinese medicine shops, they say.
Elita Lam Yee-nee, associate professor at THEi's faculty of design, first learned about recipes for making dyes from Chinese medicine while visiting Sichuan province.
"People there extract dark blue dyes from plants that are used in Chinese medicine," she says. "I thought it was a great idea. Later, at a fashion exhibition, I met a botanist who specialises in organic dye. He was willing to share his knowledge. We decided to create a database of organic dyes."
People are wrong to think dyes made from plants aren't bright and colourful, Lam says.
Even eye-catching colours, such as shocking pink, can be extracted from plants using water. The key to creating strong colours is to control the water temperature, and the length of time a plant is in the water.
"Organic dye can be easily extracted by putting a plant in water," Lam says. "Heating it to different temperatures and for different lengths of time will produce different colours. A change in acidity or alkalinity in the water will also create different colours. Using a dye on different materials will also cause variations in colours."
One researcher, Yuki Tsui Ka-yim, in the second year of her fashion design degree, says she never expected to be working in a laboratory on a fashion course.
"I studied chemistry at secondary school, and really missed working in a lab," she says. "It's great that the institute has introduced this project."
Her classmate and fellow researcher Angie Chan Tsz-ying says she enjoys discovering new colours. "Every day we'll invent a new colour from a plant used to make Chinese medicine," she says. "It's great to create something new on my own."
Lam says designers' comments about the organic dyes have been positive. She expects more and more manufacturers to use organic dyes when producing clothes in the future. "Going 'green' is the future of dyeing. Organic dye has huge potential. Consumers are now much more aware about how the products they use can affect the environment."
However, organic dyes have limitations. So far THEi's researchers have been unable to create colours consistently.
"A slight water-temperature change will affect the results," Lam says. "It would be a challenge to monitor the colour in a mass-production setting. Also some organic dyes will fade if they are ironed. But I think consumers will be able to live with these limitations once they understand that it's for the sake of the environment."