What made it difficult
Acid stain is a reaction, not a color choice. It works on the minerals in the slab, so the same product on two different floors gives two different results, and neither can be previewed from a chart.
That is the appeal and it is also the thing to be straight about in advance. Someone who wants a uniform, predictable color wants a coating instead, and should be told so before the stain goes down rather than after.
Control joints and existing marks in the slab stay visible through a stain. They can be filled and stopped from moving, but they will still read, and that is part of the look rather than a defect.
How it was done
The room masked off, walls and everything not being stained.
Stain applied and left to react with the slab, then sealed.
How it came out
An amber floor whose mottling is the slab reacting, not a pattern anybody applied.
This is the photographed work behind the San Marcos page — a real local job rather than county work standing in for one.
