What determines what denier is available ?

[John]

Reading about TB's eagerly anticipated new Halcyon fabric made me wonder why there are only specific deniers of nylon available - 1680, 1050, 600, 200 etc ?

Why not, for example, 1040 or 1060 instead of 1050 ? Is there a technical reason behind 1050 (or some other number) used ? Or is it for historical reasons ?

[Badger]

Denier has to do with the linear mass density of fibers (grams per 9000 meters). One 1d. fiber would thus weigh 1 g. per 9000 meters; one 1050d. fiber strand would weigh 1050 g. per 9000 meters. Since nylon is an engineered fiber, it could conceivably be made in any weight. What might influence the popularity of certain weights (like TB's 200d., 420d., 500d., 1050d.) is that nylon fabrics are produced in those weights by the industry-leading mills (i.e., Cordura).

The benefit of using a smaller mill like the one TB uses is that they can develop fabrics in a larger variety of weights (or other specifications) and in smaller quantities. It looks like the mill started working on Halcyon starting in 2014, so it might be that smaller mills may not have the R&D departments to churn something up overnight. It's possible that a huge company like Cordura could have developed Halcyon faster, but the trade-off is that it's unlikely they'd have any incentive to do so, given that they'd need to sell it in very large quantities to make it worth the cost of development. This is conjecture on my part, of course.