Macra Art 2 (Work In Progress)

I intend to attempt the cover again, colourising this porthole image as a starting point. I'm not sure where it will lead. Maybe I'll try and do a cover where this is the centre image, and there is less colour the farther away you get from this image? I really don't know, this could go anywhere!

One thing I have to do is work out how to colour something silver, as I don't just want to leave it black and white.