Hard Tartan

[Tobus]

I don't know why, exactly, but I've been very curious lately about hard tartan. I was reading this old thread by Matt Newsome, which went into some detail about what hard tartan is and how it is replicated today. Apparently they weave the tartan the same as any other, but it just isn't sent off for finishing/washing and is considered "in the grease". Can anyone go into more detail on what else happens in the finishing process, and how exactly it changes the cloth? Is it merely as simple as removing lanolin from the wool and working the cloth to give it more flexibility? Or does something else happen in the finishing process that softens it?

Hard tartan has been described as feeling more like canvas, and is said to be more durable as well as water-resistant. Is it possible to take a length of finished tartan cloth and do something to it in order to bring it back to hard tartan? Like adding lanolin, wax, etc?