Here is a close up view. Picture taken in old town Klamath Falls, Oregon on residential secondary circuit today 2011 deep in the heart of COPCO Country. California Oregon Power Company used colored porcelain as neutral phase indicators. OB cobalt blue and medium blue pintypes, Westinghouse light blues, mediums blues and gray signals and pintypes, Thomas grays and mottled blues and later on Victor insulator company and ITE blue colors. Spools ran the gamete. Everything from mossy green, to grays to blues of every conceivable in between glaze colors. Colored porcelain heaven!