(to be unnecessarily thorough..)

if each layer is 0-65535, the summing is as such:

layer 0 65536 / 1 = 65536
layer 1 65536 / 2 = 32768
layer 2 65536 / 4 = 16384
layer 3 65536 / 8 = 8192
layer 4 65536 / 16 = 4096
layer 5 65536 / 32 = 2048
layer 6 65536 / 64 = 1024
layer 7 65536 / 128 = 512
sum of all layers = 130,560

fitting this to a range of 256 for pixelation = divide total by 510 (256 * 510 = 130,560)

as such, i can manipulate the data for each layer without having to recalculate every layer, only resum the output....

given my b/g, using unsigned INTs seems natural to me, it's fast, it's the way i do things.. so eg. a lacunarity coefficient doesn't fit into my method at all.