From mint media

Here we have an example of a Moiré pattern. Moiré is an interference pattern familiar to anyone who has worked with halftone dots in offset printing. Here the interaction is more complex than on a standard paper stock. This is beacuse the album itself has it's own screen, formed by a radius dictated by the tracks containing the music.

The bands of interference radiate in a rosette at regular angles at a frequency of 12 times in the 360 degrees of the record. The pattern does not change when the angle of view is altered. It should be possible from this to work out the line screen used in the colour separations. The number of the line screen would probably have a relationship with the density of the grooves comprising the tracks.