What is a Dye Lot?

A dye lot is a record taken during the dyeing of yarn to identify yarn that received its coloration in the same vat at the same time. Yarn manufacturers assign each lot a unique identification number and stamp it on the label before shipping. Slight differences in temperature, dyeing time, and other factors can result in different shades of the same color between different dye lots of otherwise identical production. Although the component elements of a dye lot number are of interest only for internal business record keeping, retail yarn consumers have an interest in ensuring that they purchase a given color of yarn from identical dye lots.

Woven textile fabrics receive their color in various ways. The most common fabrics are either woven in a natural state and then piece dyed or are woven with a combination of yarn dyed and/or solution dyed yarns.

 

 

 

 

 

Piece dyeing occurs when the fibers are spun into white or natural yarn and then woven into fabric called greige-goods. After the fabric is constructed, mills then immerse the greige-goods into large tubs or vats where the color is applied to the entire roll. The dyed goods are then dried and finished in preparation for shipping. Typical dye lots will range from 300-800 yards at a time based on the weight of the yarn, the type of yarns used, and the dye tub size. This process is most often used in solid fabrics where the mill wants a broad color range. Although excellent and well performing options, piece dyed fabrics typically have the greatest color variance from one lot to the next versus yarn dyed woven fabrics.

Yarn dyeing applies color after the white or natural fibers have been spun into yarn. Dyeing occurs when the yarns are wound onto cones and placed into a high pressure tube where the color is applied onto and through the yarn through pressure dying. After drying, the yarns are woven into a constructed piece of fabric. Cotton, rayon and linen yarns are often yarn dyed and commonly used for multi colored fabrics such as woven stripes, gingham checks and plaids.  

Solution dyeing is commonly used on synthetic yarns like polyester, nylon, polypropylene and acrylic. In this process, color is mixed directly into a liquid solution before being extruded into long fibers and then spun into colored yarns thus making them extremely colorfast and consistent. That is why many outdoor fabrics, such as Sunbrella, are woven with solution dyed acrylic or polyester. This process yields large volumes of yarn so typically solution dyed yarns are used in the warp for both commercial and decorative fabrics. These colored fibers are then woven into finished goods often using yarn dyed goods in the filling.  Color consistency on these types of products is excellent.

During the color dyeing process, the batch of yarn or constructed fabric is assigned an identification number recording the specific color formula it received. Even though the same dyes are used every time, noticeable color variations can occur especially in piece dyeing of finished goods.

What causes color variations in dye lots? Temperature, time, water source and human error all contribute to slight variations between dye lots. The difference can be subtle to extremely visible. Industry standards allow up to a 6% difference in a color variation. DrapeStyle makes every effort to insure that the fabric sample you receive is from the same dye lot as the fabric we purchase for your job. Our fabric vendors have been in business for many any years and they also do everything they can to insure consistency with their dye lots.

Because of these industry standard dye lot variations, it’s important you always purchase enough fabric of the same dye lot in order to complete your window treatments.

So if you are ordering multiple drapes and/or shades for the same room, we strongly suggest that you order them all at the same time to insure the fabric comes from the same dye lot.

If you have any questions about Dye Lots or window treatments, please contact us. We are happy to answer any questions you may have.


signature