A method for analyzing an interaction between a sample surface and a drop of liquid comprises applying the drop of liquid to the sample surface and illuminating the drop of liquid using at least two light sources. The at least two light sources are each arranged at a light source position surrounding the drop of liquid. Light reflected from the drop of liquid detecting and a sensor position on a sensor of a camera is determined for each detected light reflection. Light source positions are assigned to individual light source positions. A position of the drop of liquid is calculated relative to the sensor and an item of size information of the drop of liquid is determined. The position and the item of size information are calculated from the pairs of one sensor position and one associated light source position.