Texture layer tricks

As you can see in the picture the floor is covered with white and black tiles, but only the black ones reflect their environment. The technique behind this was first explained in detail by Ivan in this thread. In this case the material for the floor has two layers. The lower one has both black and white tiles and the reflection slider far to the right.

The top layer is basically the same texture with no reflection. To make only the black reflecting tiles of the bottom layer visible we cut out the white tiles from the top layer. To do this we replace the white tiles with red in an image editing program and then check red to be the invisible color. You could also use an alpha channel to make the white tiles invisible.

Additionally we can set a bump or roughness, but it's not really needed here. You can also play around with transparency and color mix.