> I'd also like to see any data to support this - it's dark inside a hive, comb color wouldn't seem to be a factor, unless the comb is left out in the sun.

I was quoting Langstroth, in an age where wisdom was gained from experience, not data sets. But be that as it may, there have been few studies which look at this question. One of the world's foremost experts on bee comb was H. Randall Hepburn, who worked for many years in South Africa. Unfortunately for us, he did not focus on the issue of successful wintering of bees in temperate climates. Nevertheless, he understood that a honey bee comb is a structure built over time. For example:

New brood comb proceeds from a single-phase material, pure wax, to a fibre-reinforced composite.  ... Just before pupation honeybee larvae cover the walls of their cells with silk playing out the fibres randomly so that by the end of the spinning the walls are covered by thin sheets in which the individual fibrils are readily discernible. 

Subsequently the larvae  produce, from the anus, a colourless pollen-free material and then a yellow pollen-bearing one, both of which are applied in turn to the silk base. Nothing further is known of these substances, but they invite the analogy of a size* as in paper manufacture.  [* size = a gelatinous solution used in gilding paper, stiffening textiles, and preparing plastered walls for decoration] 

Successive generations of brood apply more silk to the walls, the cells become smaller, and the mass ratio of silk greater. Thus, old brood combs are heavily impregnated with silk which is inseparable from the wax except by chemical or heat treatments. 

Hepburn, H. R., & Kurstjens, S. P. (1988). The combs of honeybees as composite materials. Apidologie, 19(1), 25-36

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