Thanks for that info Evan. It rings bells now I think about it. I think what I probably saw in the partly desaturated colour pic, in an old Signal magazine I think, was the natural colour of the pipework, which looked like it could have been red - hence the reddish brown appearance, and the reason I painted it red!
I do remember seeing pics, colour and B&W, with a group of different coloured stripes around a bunch of pipes or wires. I shall make a mental note of this for future reference!