Abstract: When a photograph is printed, its original colours are converted to those of the output medium using a rendering intent transformation. This process takes into consideration the colour properties of the paper and the printer used. gamutHeatMaps are a visualization that highlights the perceptual difference between a soft-proof of a photograph in the intended output medium, and its original. They can be used to compare different output media to determine the one that most accurately renders the colours of a given photograph.