Description: The sample is placed into a cylindrical volume, where it is wetted axially from one end using water that has specific salts in it. Several X-ray tomographic images of the sample are taken during the wetting process. The gray-value profile in the wetting direction is recorded. The salty water is visible as increased gray level. The wetting process is stopped before the sample reaches saturation. After wetting, the salt content profile is measured with micro-XRF from the surface of the sample.