The proprietary Araneum fabric used in our technical outerwear is a special double-calendared Ripstop nylon that is especially suited for packing and unfurling over time without the deterioration one tends to see with other lightweight fabrics. Our 20 denier base fabric is heated and pressed through hot rollers twice to seal the pores and make it more packable. This process of double-calendaring makes the fabric windproof without the use of any coatings and because it is naturally a higher denier fabric, it is up to 33% stronger than other lightweight 15 denier fabrics, yet just as packable (even more packable in many cases) and only 10% heavier on average. We say save the 10 and 15 denier for underwear like pantyhose and tights where denier is used accurately to indicate opacity—hardly a good measure for technical outerwear.
By closing the gaps in the fabric with the double-calendaring process, Araneum also boasts remarkable insulation properties. Heat generated by the body is trapped once the garment is sealed off so the fabric is not only protecting you from the elements, but it is also trapping in the heat that will keep the core warm during downtimes. Moreover, the heat that Araneum traps tends to be dry heat. Lacking a coating, Araneum has a tendency to absorb and dissipate vapor rather than allowing it to bead up on the surface. Then because the fabric is so thin, it dries actively with body heat leaving toasty dry heat floating between the fabric and the body. These insulation properties make it a prime choice for use with down because vapor that would otherwise soak the down is able to make its way to the exterior and either dry up or dissipate. Coated fabrics make this progression impossible so the down loses its loft and insulation properties more easily from moisture generated by the body.
CAMP uses Araneum in a large number of the garments we sell as part of our Essential Line—gear so light and so compact that you run out of excuses not to carry it with you. We use it so prolifically because it really strikes the balance of warmth v weight v packability better than any fabric we have ever seen.
Oh, by the way, we have a bunch of this past winter's down apparel that uses Araneum on blowout in our outlet area to make room for the new gear coming this fall. Now is the time if you are shopping for good deals. Here's the LINK.