As with their choice of white cotton, most clothing manufacturers prefer synthetic dyes because they are cheaper and easier to use.
However, there has been growing concern about the impact of the colouring industry on human health and on the environment, particularly when waste water from the process is often discharged with inadequate or no treatment.
While the use of harmful chemicals has drawn the most attention, green groups argue we should be conscious of the whole process. The National Resources Defense Council (NRDC), an influential American NGO, identifies the impact of dye mills from three main factors: discharge of untreated or poorly treated effluents, continued use of hazardous colouring agents and poor plant management resulting in a waste of water, energy and chemicals.
Laurie Lemmlie-Leung - general manager of textile manufacturers Sapphire International, which owns Breganwood Organics - agrees.
"When you're working on something for the environment, it's not just what's in the dyes, but also how you treat the effluent from the dyeing process," she says.
Lemmlie-Leung launched the Hong Kong Organic Textile Association last year to counter widespread misinformation in the marketplace about organic clothing.
"A lot of people think if [a fabric] is labelled organic, it just means it's soft. It can be soft, of course, but that's because of the type of yarn or the way it was manufactured," she says.