This hair is highly sought out for its 'virgin', untreated qualities, as well as its great length. From there the hair is cleaned and the color is removed before being re-dyed for international style tastes. Artificial hair colors:  Manufacturers of artificial hair use a standard scale to classify the hair by color. The lower the number on the package, generally, the darker the color. 1 usually denotes darkest black, and would become lighter with increasing number value, ending at the lightest blonde, then finally white. These colors vary greatly from one manufacturer to another, and certain specialty hair suppliers also create their own signature patterns and colors. Human hair colors:  Come in an endless variety from platinum blonde to darkest natural black. True raw blonde human hair is scarce and is highly sought after. Textures of artificial hair vary from very straight to extremely curly, or kinky. The exact names of curl patterns vary by brand, and the possibilities of curl patterns with synthetic hair are endless, but some examples of packaged textures include:  Textures of human hair vary from very straight to extremely curly or kinky, and all the naturally occurring textures that are in-between. The exact curl patterns vary by person and so the possibilities of curl patterns with true raw hair are endless. The misnomer of 'tracks' comes from the common, long-lasting method of integrating wefts, known as the 'track and sew' method. The 'tracks' are usually cornrows, braided in the direction of how the hair will fall. Toward the face or away, with or without a part, the tracks build the foundation of how the end result will look. The wefts are then sewn onto the braids, usually with a specially made, blunt-ended needle. The needle can be curved or straight. There are many different colors of specially-made thread to choose from, depending on what color of hair you will be integrating. Darker hair lends to darker thread. When the hair is braided at a high level of tension, the client is at risk for traction alopecia. Wefts may also be bonded directly to the clients hair using special bonding glue. Care must be taken not to bond the wefts directly to the scalp, as it can cause sensitivities in some clients. A patch test is frequently recommended, as per manufacturer's directions. Glue has become less popular since it was discovered that glue can cause severe and often permanent health issues such as headaches, bald spots and dermatitis. The "invisible part" is a technique used by hair stylists that hides any evidence that the person is wearing an extension.