So, as I stated previously, I'm not overly happy with the colour of the stone I chose to use on the Basement of the San Franciscan, it's a pretty colour but, I don't like it for this particular project. It doesn't feel basement-y enough for me. :D
The stone (Andi Mini Cut Stone in Brown) is made of plaster and therefor porous, which led me to believe I should be able to paint or wash it to tone down the pink.
I tested washing it with a muddy grey wash, but it just made a mess and collected in all the little grooves of the stone making puddles of colour. It also was too wet, saturating the plaster and making it very delicate & crumbly. Additionally, it flattened out the colour variation of each stone making them look less dynamic.
Next I decided to try my Brushmarkers. I bought these a while ago after seeing a Greenleaf forum member have great success colouring egg carton stone with them.
I figured the principle would be the same with the plaster so I did some tester pieces using cool & warm grey's 1, 2, & 3. The lightest greys hardly changed the stone at all, so in the end I used the two darker shades of grey the most. I used each marker randomly around the walls for some variation.
The stone still shows through it's just now more of a muddy pink than bright pink. Better for a basement I think...
I'm using Jo Sonja's Matte Varnish to seal the stone before mortaring. You can get it from Spotlight or Bunnings. I don't want the grouting material to stick to the stone too much, or change the colour again so I think this step is important.
And here it is all varnished and ready for mortar... Not a huge change but enough to make me feel like I no longer have a Barbie house!