Sophisticated surface science techniques long familiar to materials researchers are now being used routinely to characterize the colloids found in papermaking systems. Ion Scattering Spectroscopy (ISS) is used to obtain the surface elemental composition of inorganic filler pigments. Laser light scattering is applied to the determination of particle size and particle charge distribution by way of the methods of Photon Correlation Spectroscopy (PCS) and Doppler Electrophoretic Light Scattering (DELS). The heats and races of interaction of hydrophilic colloids (water soluble polyelectrolytes) with hydrophobic colloids are determined by batch titration microcalorimetry.