An application of optical tensiography is described for studying protein adsorption/desorption/crystallisation processes. This paper concentrates on investigating the physics of the surface kinetics and associated crystallisation processes of the serum protein BSA. The measurements show changes in optical transmission caused by the development of protein layers on surfaces inside a liquid drop. Various absorption mechanisms are evaluated and a physical explanation suggested for the results involving changes in optical scattering as the structure of the protein layers develops. It is shown that tensiography provides a powerful real-time method for monitoring protein adsorption processes on a solid substrate that gives new insights into protein kinetics on these substrates. The study reveals results that are in agreement with earlier work showing multilayer structures and perhaps rearrangement of complex protein layer structures. Finally, consideration is briefly given to potential applications and most importantly the experimental development of this new tensiographic approach for improved real-time absorption measurements of proteins on solid substrates. \circledC 2010 Elsevier B.V.