Many colour schemes used to display astronomical intensity images do not have an underlying increase in the perception of the brightness of the colours used (e.g. burning out to red for the high data values, but using yellow/green for intermediate data values, which are perceived as being brighter than the red).
I have written up the implementation of a colour scheme — called `cubehelix’ — which is intended to be perceived as increasing in intensity. This is a goes from black to white, deviating away from a pure greyscale (i.e. the diagonal from black to white in a colour cube) using a tapered helix in the colour cube, while ensuring a continuous increase in perceived intensity. This colour scheme prints as a monotonically increasing greyscale on black and white postscript devices.
The method costs people’s time according to how much they earn, and uses this cost to create a value for the development. So, for example, it says the market price of an hour spent travelling in a taxi is £45, but the price of an hour spent travelling by bicycle is just £17, because cyclists tend to be poorer than taxi passengers.