Mike, it's the combo. Fomatone is a warmtone paper and PW is a developer developed to be used especially with this paper, to emphasize brown tones. The scanned picture doesn't perfectly match the actual print; the print is a bit warmer.
Very powerful image, the mind sees what is there but the spirit feels more than what is seen. It works very well to convey the scale and pathos of humanity overlaid with the patina of time. More, please!