Editing Yarn (section)

=== Comparison of material properties ===
[[File:Restored primary level spinning machine at Quarry Bank Mill.jpg|thumb|left|190px|A fully restored Derby Doubler, winding a sliver lap ready for finisher carding at [[Quarry Bank Mill]] in the UK]]
In general, natural fibers tend to require more careful handling than synthetics because they can shrink, [[felt]], stain, shed, fade, stretch, wrinkle, or be eaten by [[moth]]s more readily, unless special treatments such as [[mercerized cotton|mercerization]] or super washing are performed to strengthen, fix color, or otherwise enhance the fiber's own properties.

Some types of protein yarns (i.e.,&nbsp;hair, silk, feathers) may feel irritating to some people, causing [[contact dermatitis]], [[hives]], or [[wheeze|wheezing]]. These reactions are likely a sensitivity to thicker and coarser fiber diameter or fiber ends.<ref>{{Cite web|last=Shakespeare|first=Margaret|date=September 30, 2015|title=20 Things You Didn't Know About...Wool|url=https://www.discovermagazine.com/planet-earth/20-things-you-didnt-know-about-wool|access-date=2021-11-25|website=Discover Magazine}}</ref> In fact, contrary to popular belief, wool allergies are practically unknown. According to a study reviewing the evidence of wool as an [[allergen]] conducted by Acta Dermato-Venereologica,<ref name=pmid28350041>{{cite journal |last1=Zallmann |first1=M |last2=Smith |first2=P |last3=Tang |first3=M |last4=Spelman |first4=L |last5=Cahill |first5=J |last6=Wortmann |first6=G |last7=Katelaris |first7=C |last8=Allen |first8=K |last9=Su |first9=J |title=Debunking the Myth of Wool Allergy: Reviewing the Evidence for Immune and Non-immune Cutaneous Reactions |journal=Acta Dermato Venereologica |date=2017 |volume=97 |issue=8 |pages=906–915 |doi=10.2340/00015555-2655 |pmid=28350041 |doi-access=free |hdl=10072/355515 |hdl-access=free }}</ref> contemporary superfine or ultrafine Merino wool with their reduced fibre diameters do not provoke itch, are well tolerated and in fact benefit [[Dermatitis|eczema]] management.<ref name=pmid28350041/> Further studies suggest that known allergens applied during textile processing are minimally present in wool garments today given current industry practices and are unlikely to lead to allergic reactions.<ref>{{Cite web|title=Are you allergic to wool?|url=https://www.woolmark.com/fibre/are-you-allergic-to-wool/|access-date=2021-11-25|website=www.woolmark.com}}</ref>

When natural hair-type fibers are burned, they tend to singe and have a smell of burnt hair; this is because many, like human hair, are protein-derived. Cotton and viscose (rayon) yarns burn as a wick. Synthetic yarns generally tend to melt, though some synthetics are inherently [[Fire-retardant fabric|flame-retardant]]. Noting how an unidentified fiber strand burns and smells can assist in determining if it is natural or synthetic, and what the fiber content is.

Both synthetic and natural yarns can [[Pill (textile)|pill]]. Pilling is a function of fiber content, spinning method, twist, contiguous staple length, and fabric construction. Single ply yarns or using fibers like merino wool are known to pill more due to the fact that in the former, the single ply is not tight enough to securely retain all the fibers under abrasion, and the merino wool's short staple length allows the ends of the fibers to pop out of the twist more easily.

Yarns combining synthetic and natural fibers inherit the properties of each parent, according to the proportional composition. Synthetics are added to lower cost, increase durability, add unusual color or visual effects, provide machine washability and stain resistance, reduce heat retention, or lighten garment weight.