What does Loop Dyed mean?
An major industrial method for dyeing indigo yarns.
Heddels explains Loop Dyed
Loop dyeing was the first method used to dye denim. It involves pulling ropes of yarn through a vat of indigo dye then out up onto the roof of the factory, allowing the yarn time to oxidize before returning to the dye bath. Loop dyeing creates more consistent indigo shades and requires less space to operate than other dyeing process.
Loop dyeing machinery: