Pigment particle coagulation is an important step in the formation of an inkjet image. The size of the formed colorant flocs determines how deeply the colorant penetrates into the substrate and hence has a significant impact on image quality (optical density, gloss, chroma, etc.). Many factors (e.g. charge density) determine the colorant coagulation rate and an in-depth understanding of these factors is needed to assist in the design of advanced colorants for inkjet applications. This study focused on a series of pigment particles that had been chemically modified using Cabot's patented surface modification technology. When the pigment was de-stabilized under various triggering conditions, such as ionic strength and pH, particles started to coagulate. The rate of coagulation was measured by monitoring the time evolution of the floc size as determined by dynamic light scattering (DLS). A characteristic coagulation time, τ, was derived from fitting the DLS data. The impact of trigger condition and surface modification type on the coagulation time, τ, was determined and provides critical insight as to how the pigment coagulation can be controlled to yield optimal print performance.