Why do my new sheets have blue and red threads woven into the yarn?

What are they? Are the sheets faulty?

Have you had this experience – blue and red marks on brand new, expensive sheets?  These marks are referred to as ‘contamination’.

Contamination of cotton fiber affects yarn and the fabric produced from it.  This happens when foreign material (plant-based or synthetic material and even metal) gets mixed with the cotton during manufacturing. This could include during collection, processing, production, handling, or storage.  It can consist of plant material deposited from the manufacturing plant during harvesting and/or transporting, and from baling such as burlap, nylon and polypropylene.  Contamination appears as a thread woven into the fabric or a small inconsistency in the colour of the item.

Most end-users demand parameters as small as 1mm or even zero contamination in the yarn or fabric without understanding the realities of the process. Those who understand the process, accept certain low levels but even these levels are not easily achieved by spinners. Over time, technologies have been developed to detect and remove foreign material in the blow room and bobbin processes. But it is not possible to completely remove foreign material from the yarn.  Furthermore, prior to spinning, the yarn is checked electronically on the winding machines which can detect contamination greater than 1cm. 

There are no globally established standards for the accepted size and frequency of contamination in knitted and woven fabrics.  Generally, in the textile industry 30-40 spots below 2cm / 100 meters is considered acceptable.  Vendella have set even higher standards, accepting only 2 marks per square meter.

Contamination, even if it is a tiny single fibre, results in the downgrading of yarn, fabric and sheets to “seconds quality”, and at Vendella we are continually collaborating with our manufacturers to maintain the balance between cost and quality on our sheets.

https://www.youtube.com/watch?v=OYZ-QsA3gmQ