"Cylinder number 1 starved of fuel, outlet from distributor partially blocked. Spark plug cylinder number 1 black soot deposit "

I'm no expert, but if a cylider is starved of fuel, black soot should not be a problem on the same plug. Fuel starvation would result in a lean condition.

Check these images out. Site loads slow.
http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html