Sometimes the terminology gets in the way. My study group is going to be working on color-and-weave. I have been reading about this but all I find is shadow weave. I have read about the Powell and Atwater methods, but nowhere does it tell me if color-and-weave is one structure and shadow weave is another structure. My question is: Should I be looking for two different structures (threadings) or are they the same with just a different way to describe them?
Color-and-weave is not a weave structure (and, in a way, neither is shadow weave, though it has certain structural qualities). Color-and-weave (loosely described) is any single-layered structure where your eye sees a pattern created by one colorway created by both warp threads and weft threads vs another color way created by both warp threads and weft threads. So instead of reading the design as warp color vs weft color (the way you would in a twill) you see one color of both vs another color of both.
Log cabin is such a structure and so is shadow weave. In these two, though, the colorways alternate thread by thread in both warp and weft. Color-and-weave threadings and treadlings can also show any number of threads of one colorway alternating with any number of threads of the other colorway.
Usually, log cabin can be thought of as a 2-block shadow weave. Because of the way shadow weave (with more blocks) was usually threaded, it wasn't considered a block weave before Marian Powell (I think, anyway). In essence, both log cabin and shadow weaves are block weaves where the two different interlacements (pattern vs background) are horizontal lines vs vertical lines. Structurally, log cabin and shadow weave are primarily plain weave with 2-thread floats (in the case of shadow weave) at the edges of block changes.