Speculating: I would expect silica changing the hue characteristics of some pop processes (such as Argyrotype, Ziatype...) which are highly sensitive to humidity, towards cooler tones because silica would retain moisture.

Any real life experiences? I have only tried a couple of prints with silica and despite I liked the contrast / hue and dmax it gave, I left it aside because of streaking. I'm perfectly happy / satisfied with the traditional methods...