1. An image enhancement system for enhancing digital images, the system comprising: (a) a non-transitory computer-readable memory; (b) an electronic interface; and (c) a computer processor configured to: (i) receive, via the electronic interface and store in the computer-readable memory, a digital image comprising a plurality of pixels, each pixel having a value in a first three-dimensional colour space; (ii) receive a mapping of values in a subset of the first colour space, the mapping specifying a modified colour value for each colour point in the subset, the mapping having been calculated by selecting a reference point in the subset and, for each colour point in the subset, mapping the colour point to the modified colour value offset from the reference point by a modified colour point vector calculated based on the colour point vector extending from the reference point to the colour point, the colour point vector having a direction and a magnitude; (iii) apply the mapping to the pixel values in the digital image falling in the subset to produce an enhanced image.