Provided are an artificial hair fiber having a soft texture and appearance close to human hair, and being light in weight; and a head accessory including the artificial hair fiber. A polyamide fiber for artificial hair includes a resin composition that includes a polyamide resin as a primary component resin, and is a hollow fiber having a void in the cross-sectional center section, the void percentage of the polyamide fiber is 15-40%, the fiber specific gravity of the polyamide fiber is 0.80-1.10, and the bend rigidity of the polyamide fiber is 1.5×10.sup.−3 to 5.5×10.sup.−3 gf.Math.cm.sup.2/yarn.

A method of installing a wig on the head of a wearer, the wig having a top portion that defines an opening corresponding to the wearer's part, the top portion being composed of a fabric and having wig hairs attached to the top portion. Wig clips attach the wig to the wearer's natural hair on the opposing sides of the wearer's part so that the wearer's natural part is exposed. The wearer's natural hair is not disposed over the fabric at the edges of the opening. Alternatively, a leave-out of the wearers natural hair does not cover the wig hair adjacent to the edges of the opening. The wig hair adjacent to the edges of the opening may be tangled or the installer may tease the wig hairs adjacent to the edges of the opening. The invention is also a wig for application of the method.

A polyvinyl chloride-based fiber for artificial hair that has excellent low glossiness and grip performance when woven and can be stably spun. Configuring a fiber for artificial hair using a polyvinyl chloride-based resin composition, wherein the polyvinyl chloride-based resin includes, at predetermined blending amounts, a polyvinyl chloride-based resin (A) having a viscosity-average polymerization degree of 450-1,700 and a crosslinked vinyl chloride-based resin (B) in which the viscosity-average polymerization degree of a component that dissolves in tetrahydrofuran is 1,800-2,300, the difference between the viscosity-average polymerization degree of the polyvinyl chloride-based resin (A) and the viscosity-average polymerization degree of the THF-soluble component of the crosslinked vinyl chloride-based resin (B) is in a predetermined range, and the cross-sectional shape of the fiber for artificial hair has a first projection, a second projection, and a third projection and the lengths and widths thereof satisfy predetermined conditions.

A human hair fiber treatment agent for treating human hair fibers separated from the human head and artificially fixed at one part of the longitudinal direction, wherein the human hair fiber treatment agent comprises the following components (A) to (C) in the formulation thereof, and the content of the component (A) is 1% by mass or more: (A): formaldehyde or a hydrate thereof; (B): a melamine derivative represented by the formula (1) wherein R.sup.1 to R.sup.3 each represent a hydrogen atom, a hydroxymethylamino group, a hydroxy group, a halogen atom, a phenyl group, a linear or branched alkyl group or alkenyl group having 1 or more and 6 or less carbon atoms, or a linear or branched alkoxy group or alkenyloxy group having 1 or more and 6 or less carbon atoms; and (C): water.

##STR00001##

A fiber treatment agent can provide artificial hair fiber with smooth and dry texture. A fiber treatment agent includes water; silicone oil; and ionic liquid. Content of the sum of the silicone oil and the ionic liquid with respect to the water is 2 parts by weight or more and less than 10 parts by weight. Content of the silicone oil with respect to the weight of the water is more than 0.5 parts by weight and 9.5 parts by weight or less. Content of the ionic liquid with respect to the weight of the water is 0.2 parts by weight or more and 5.0 parts by weight or less.

A fiber treatment agent can provide artificial hair fiber with softness. The fiber treatment agent includes a cationic polymer having a structural unit derived from diallyldimethylammonium chloride (DADMAC), and content of the cationic polymer is 0.02 to 0.5 weight %. The cationic polymer preferably has a structural unit derived from acrylamide. Preferably, the fiber treatment agent further includes an antistatic agent, and content of the antistatic agent is 0.2 to 5.0 weight %.

A fiber treatment agent can provide artificial hair fiber with softness. The fiber treatment agent includes a cationic polymer having a structural unit derived from diallyldimethylammonium chloride (DADMAC), and content of the cationic polymer is 0.02 to 0.5 weight %. The cationic polymer preferably has a structural unit derived from acrylamide. Preferably, the fiber treatment agent further includes an antistatic agent, and content of the antistatic agent is 0.2 to 5.0 weight %.

A system for the viewing and selection of hair products includes a processor configured to obtain customer identification information characterizing one or more characteristics of a customer and to obtain customer measurement information characterizing one or more physical measurements of the customer. The processor also obtains selected product information characterizing a selected hair product of the customer and sends finalized order information regarding the selected hair product.

A system for the viewing and selection of hair products includes a processor configured to obtain customer identification information characterizing one or more characteristics of a customer and to obtain customer measurement information characterizing one or more physical measurements of the customer. The processor also obtains selected product information characterizing a selected hair product of the customer and sends finalized order information regarding the selected hair product.

A device for providing safety during the process of installing eyelash extensions onto the natural eyelashes of a subject, especially when the installation is automatic. In some embodiments, the placing of extensions is carried out by a robotic mechanism utilizing computer vision, and in some embodiments, a barrier is created between the robotic mechanism and the subject in order to protect the subject in the event of a malfunction.