Rheology is the science of deformation and flow of materials. It describes how liquids and semi-solids move in response to a force (Figure 1) [6]. Viscosity (symbol: η; units: mPa.s or cP) is then defined as the resistance to flow of the liquid and can be calculated by the ratio of the shear stress (τ; mPa) to the shear rate (γ; s-1). There are many options when choosing equipment to measure viscosity, but the most versatile for paint analysis is a controlled stress (or controlled rate) rheometer, which measures the force needed to rotate a flat or conical plate in ...