Colourfast

Colourfast

Textiles can be dyed at the fibre, yarn, fabric of product stage.

Fabrics are often produced in a greige – undyed state and then piece dyed to meet the colour requirements of the maker up and the selling season. The fabric is passed through a bath of dyestuff and then squeezed between rubber rollers to ensure even and consistent dyeing.

Garment dyeing enables colours to be chosen late in the manufacturing cycle, as dictated by fashion. This is desirable and cost effective for some manufacturers because colour decisions can be made close to the selling season. This is often used on fashion products.

 

Image above: the blue dye in the stripe fabric has bled and turned the white areas of the fabric a pale blue. This is an example of POOR colour fastness - i.e. the colour has NOT stayed on the fabric

Colour fastness is the RESISTANCE to colour loss during the manufacturing process and in use. A wide range of colourfastness exists for different fibre type and blends. Fastness depends on the type of dye and fabric and there is no universal colour that has the same level of fastness on all types of fibre. Also, different end uses have different fastness requirements. Underwear needs to be fast to perspiration.  The ISO 105 standard for fastness: resistance of the colour to rubbing, resistance to washing determines the wash programme that can be used – dyes are expected to be fast to the wash programmes at 60 degrees.  Resistance to perspiration is very important in underwear, outerwear and sportswear.