Understanding Thread Types In Embroidery

Almost all commercial embroidery is stitched in 40 weight polyester or rayon thread. Polyester is stronger and survives hot washing, bleach and industrial laundering. Rayon has a higher sheen and a softer, more luxurious look but gives up durability to get it. Everything beyond those two, metallics, mattes and novelty threads, is a specialist decision that costs machine time and needs the design built around it from the start.

Thread Weight, And Why 40 Is The Default

Embroidery thread weight uses counterintuitive numbering: the higher the number, the finer the thread. 40 weight is the industry standard because it covers well without needing a punishing number of stitches. 60 weight is finer and is used for small lettering and delicate detail, but it takes more stitches to fill the same area and the machine runs slower. 30 weight is thicker and gives a bolder, more textured look with fewer stitches, at the cost of fine definition.

Polyester: The Workwear Default

Polyester thread is colourfast, abrasion resistant and largely indifferent to hot washes and chemical cleaning. It will not lose colour to bleach-based laundry processes, which is the reason it dominates hospitality, healthcare and industrial uniform. It also has a small amount of stretch, which helps it lie flat and reduces thread breaks on the machine. For anything worn daily, laundered hard, or issued as kit that has to still look right in two years, this is the answer and there is not much to debate.

Rayon: Sheen At A Price

Rayon is a viscose-derived thread with a brighter lustre than polyester. It lies beautifully in satin stitch and gives a logo a slightly richer, more finished look, which is why it stays popular for fashion, retail and hospitality pieces that are seen close up. It is weaker, though, and it does not enjoy repeated hot washing or chlorine. If a garment is going through a commercial laundry, rayon is the wrong choice regardless of how good it looks on the day it is delivered.

The Sheen Direction Problem

Here is the thing that catches most buyers out. Thread reflects light along the direction it lies, so stitches running one way catch the light differently from stitches running another. In a single-colour logo with a curved satin outline, one side of the curve can look noticeably lighter than the other under office lighting. Nothing has gone wrong. It is how thread works. A good digitiser manages it by controlling stitch angles deliberately, so if your mark is symmetrical and the two halves must look identical, say so before the file is made rather than after the first sew-out.

Specialty Threads And What They Cost You In Practice

• Metallic: fragile and prone to breaking, so the machine runs slower and every garment in the run takes longer.
• Matte and cotton-look threads: no shine, ideal for heritage and outdoor brands, but generally less colourfast.
• Glow and reflective: eye-catching, limited palettes, and the effect depends heavily on stitch density.
• Neon and fluorescent: rarely a close match to a printed brand colour, so agree the shade from a physical card.
• Variegated: unpredictable on small elements where a colour shift can land in the wrong place, better on large fills.

Matching Thread To A Brand Colour

Thread comes in fixed shade cards, one per manufacturer, and nothing is mixed to order. Matching a brand colour therefore means choosing the closest available shade, and the closest available shade differs between thread brands. Judge it from a physical card, in daylight and again under the artificial light the garment will usually be seen in, not from a screen. Sheen matters too: a satin-stitched thread reads lighter than the same colour printed flat, so a thread that looks correct on the card can look a shade pale once it is stitched. Experienced embroiderers often pick one step darker for exactly this reason.

Bobbin Thread, Quietly Important

The bobbin thread is the one nobody discusses. It is usually a finer white or black polyester and it forms the underside of every stitch. It is visible on the reverse of the garment, and on unlined caps and lightweight fabrics a dark bobbin can shadow through to the front. It also affects tension, which affects how cleanly satin stitches sit. It is a small detail that only becomes noticeable when it is wrong.

“"Thread has no Pantone book. It has a shade card and somebody's eyes on a grey Tuesday."”

What To Specify When You Brief

Tell the embroiderer how the garment will be laundered, because that alone settles polyester versus rayon. Name the brand colours you are trying to hit and ask which shade numbers were chosen. If the logo has symmetry that must read evenly, flag it. And if somebody is pushing metallic thread for a large fill, ask what it does to the production time before agreeing, because it is a finishing touch rather than a body colour.