We build a lot of different sling configurations, and one option that we discuss with customers are the different available rope coatings.  OPTION 1: Pretty much all raw rope is white when it is uncoated.  Rope factories can color rope by running the white "uncoated" rope through a tank filled with a coating solution - frequently water based.  This coating style achieves good color penetration and usually ends up coating at the fiber level, providing a measure of protection against UV exposure, etc.  For example, the default factory coating color for Cortlan's popular Plasma HMPE rope is 'factory purple', and many off-branded HMPE winch lines and soft shackles sold today are "factory grey". OPTION 2: Rigging shops like ours will often purchase "uncoated" white rope, and then apply a PolyEurethane-based external coating.  These 'external coatings' typically do not penetrate as deep as a water-based dye coatings, but they are more functional, sealing the rope strands.  This helps to keep dirt and debris away from the load-bearing fibers at the center of the rope strands.  Abrasives are kept on the rope's surface where they are easy to wash away, making the rope far easier to keep clean.  External coatings can look thicker than factory-applied coatings, and they will initially make the rope feel stiff, but once the rope is used a few times it will loosen up nicely.  For many people, the less expensive 'Factory Coating' is sufficient, while for people operating in exceptionally abrasive or dirty environments - or people who are using their gear constantly or just love vivid colors - the External Coating option makes more sense.