Colour is an important part of how most of us see and perceive the world. Colour impacts our day-to-day lives whether it is colours we see in nature or colours reproduced on electronic displays. While the average American now spends eight hours a day looking at some form of electronic display, reproducing and using colour effectively on electronic displays has remained a challenge. Using colour well on computer displays has been of special importance to information visualization researchers and practitioners, artists, and designers who use colour in their work to express ideas, concepts, emotion, data, and information. In the field of information visualization, colour is commonly used for the purposes of encoding of additional dimensions of data. Knowing which colour choices to make when encoding data in information visualizations systems and information graphics is often difficult and often comes down to a case of trial and error or aesthetic choices by the designer. In this thesis, I address issues of digital colour use including, a) how can people better understand the colour choices of artists and designers by visualizing the colour data extracted from large digital image sets, b) how can we visualize abstract concepts and ideas using relevant colour information, and c) how can we computationally help inform visualization designers to know more about the accessibility of their colour choices and assist in balancing aesthetic and perceptually different colour choices in their visualizations. I present a novel visualization approach and two digital tools, ColourVis and ColourSafe that address these outstanding research questions. Through ColourVis, I offer an exploration and comparison tool for individual paintings, groups of paintings and trends in colour usage over time. ColourSafe helps inform information visualization designers, artists, and researchers about the colours they use in their visualizations. By using such tools, designers and artists are more informed about the colour palettes and choices making up large groups of images and be able to choose colours that are both aesthetically pleasing and accessible to a wide audience in their own work.