Abstract: A generalized grain ruler incorporating a plurality of uniform patches representing a range of granularities, each patch being a perceptually distinct representation of graininess spaced at perceptually uniform intervals and recorded in an increasing sequence of graininess. A method for producing a generalized grain ruler for the measurement, by comparison of, grain in a reference imaging system generated image, comprising, the steps of:a) generating a set of random numbers for each image component;b) filtering each set of random numbers to alter the Wiener spectrum to result in a filtered set of random numbers that look as if they were generated by the reference photographic system; andc) delivering the filtered set of random numbers to an output device that renders them into an image which is the generalized grain ruler.