Originally Posted by dongeri
Crocking is the fading of indigo that occurs when the denim/fabric is rubbed against something. I'm sure you could use crocking as a term to describe what makes whiskers and fades in general. As for the resin treatment: Jeans that has a deep indigo dye and is NOT treated with resin makes your hands blue if you rub them. Resin does NOT, however, prevent your jeans from fading the usual way (whiskers and all that). Somebody correct me if i'm wrong.
You're not wrong
Just to add a little to both topics ; Crocking is the general term used to describe the rub-off of colour from one fabric to another surface, and is not indigo specific. It can apply, for example, to a red pigment dyed twill crocking onto a white leather sofa. Red being a notorious crocker. It is true that resin will prevent, or rather, lessen crocking to a certain extent by covering the surface of the indigo with a polyurethane or acrylic resin and by extending that logic, that dark blue denim jeans untreated by resin tend to crock a lot more. However, as always, there are exceptions, notably 45rpm's deep purple-blue Jomon's & it's brethren (There's an even more expensive, light-weight leftie, natural indigo 45rpm with the same dye holding properties) that hardly crock at all. The resin is used for various effects and can be applied via spray or by dip and then polymerised (hardened) by baking in an oven or on grills, rather like the ones used by kebab shops
As well as preserving the dark indigo by protecting it against abrasion, it can act as a stiffener, like starch, to hold the semi-permanent 3D whiskers that are commonly seen on jeans this century. Resin can also be coloured, such as Adriano Goldschmied's use of metallic resins in his Goldsign collection. There are downsides. By adding stiffness you add brittleness. It's easy to over cook the resin, rendering the denim brittle and fragile (again, much like over starched jeans), lowering the tear strength and making them prone to ripping. This leads to higher risks in production of wastage, and higher customer returns at the retail end. Resin coating also effects the permeability of jeans, both to air and water, so that you'll sweat more in heavy coated jeans. For further info, there's a nice patent description on the World Intellectual Property Organisation's site regarding the use of resin - in this case, an acrylic resin by Cognis, the Italian chemical company. http://www.wipo.int/pctdb/en/wo.jsp?...6&DISPLAY=DESC