Carey Lea, or his silver, but now find the term refers to a fine 500nm or so silver or reduced silver complex with this peculiar and recognizable red/yellow tint to it.
But nanoparticles and rods, and their effect on lightwaves and color are something that I have studied and even built nano antenna arrays described here.
In this image are two FP-100B negatives, and Fuji's low silver negative, cheaper to produce, is apparently filled with silver halide grains that are quite tiny, and probably much smaller than a micron, maybe half or even a quarter that. Mie scattering and nanoparticle size analysis with spectrometers show that in general there is a direct relationship between size of a scatterer (or the average sizes of scatterers) and the average wavelength reflected and transmitted. If this is the case here, we can say there is some distribution around yellow, and it looks a lot like the same hue we achieved with our recent DTR, below, and monochrome images from TIP, below that. It also looks like the color of iodine.