RS Motorsport :: Classic Speed Restored

I have converted the xflow to run ulp and have found that reading the plugs as a base line for a tune up is a little different. When the engine would not idle well the plugs were clean ie no deposits at all. Not grey not black not white just as if your had pulled em out the box!!. Now the car has a resonable idle,(i uped the idle jest a bit)pull a plug and its black as. So how does one read plugs for ulp?

Cool, So black plugs that come out would be Carbon build up ?
ie dodgy camrys that people never service.