To paint a wall to look like stone, use a variety of tools, several different glazes and painter's tape to tape off the grout lines. Layer up the different colors before blending and texturizing them with helpful tips from a professional artist in this free video on painting techniques.
We are going to talk about painting stone. How to make your walls look like painted stone. The first thing you want to do is decide or determine the size of your block work. Once you have determined your block size it is very important to use a measuring tape, probably a pencil to draw your lines on your wall and a level, several sizes of level will be necessary to make sure that your lines are drawn straight. I use references all the time for my work. This one happens to show different methods of openings to create around your stonework so you don't think you are in a prison or in an elementary school. It isn't really important to draw a heavy line, you can just do dashes so you don't have the line to contend with when you pull your tape because when you pull your tape what's going to happen is that the painted work is around the tape and then when you pull the tape that will become the grout line, the negative space that you have not painted. This particular method of painting your walls to look like stone using tape to mask out your grout lines, I'm just going to use a random selection of tools, a sponge, a couple of brushes, on a larger wall I would use a little bit larger of a brush so all I have here in my little paint tray is paint with primer paint that has been tinted of blondish color. It is probably what I have on my board for primer. I have some glazing liquid which will make it a little more transparent and then these are universal tints that will alter my color so by adding just a little bit of this raw umber and taking my brush and perhaps starting with this block I'm just going to scumble the glaze on to and treating each block as an independent unit and the initial color on there and then you can take a sponge and create some movement so this direction say is coming from this edge to this corner. I would look at stone and would highly recommend looking at what you are trying to mimic before you mimic it. It doesn't just exist in your brain, look at different types of stones, pick apart the colors that are involved and then mimic them. Now I'm taking my sponge to model this stone. This is going to be a very simple technique that would be good first layer and I will just show you what happens when you pull the tape at this point. You have, I'm going to stick this back on there like this to give you an idea of how you end up creating an initial grout line. The second step on the painted stones on your walls we have already glazed them and now I am going to do another glaze over the top. So I'm going to apply the varnish pretty much out of the can and I have some white paint just generic linen white here at my side and I'm going to add that to the isolated block that I'm working on and I'll just soften that with my sponge just so it doesn't look so brushed on and a little bit of darker color put on with your sponge and create a different type of movement in your stone by just dragging and wiggling the sponge through the glaze, that's that.