On Monday morning, the 26th, it was easily evident that the floor needed another layer of acid dye. The color wasn't horrible, but it was a very orange-y rust. Not exactly what we were going for, and we knew we could do better. Because we now knew (from the previous day's experience) that creating the color we wanted required only a quick going-over with the darker color and a more thorough soaking with the lighter (both colors weren't being applied in the same quantity), I was able to relieve our timber framer of Flooring Detail duty and take over the project with dueling Hudson sprayers in hand.
After the dye had completely dried, a liberal washing of the slab (to neutralize the acid) ensued. (Along with more of the aforementioned hauling of water from the river down the road.)
Tuesday morning brought the desired effect to the floor, and the compass rose looked fantastic! I'd say the floor looks like dappled, worn leather: softer in some places and deeper and darker in others. All in all, it was a fantastic way to make a plain ol' grey cement slab look like a million bucks! However, the final job of waxing it to seal in the color still lay ahead . . . .