How do I read the color of a spark plug? Look at the firing tip of your spark plug while paying close attention to the condition and color of the ceramic insulator and the metal electrode. Observe the color first. Light tan or gray deposits are normal, and an indication that everything is working well.
Definition of candle. 1  1 : a usually molded or dipped mass of wax or tallow containing a wick that may be burned (as to give light, heat, or scent or for celebration or votive purposes) 2  2 : something resembling a candle in shape or use a sulfur candle for fumigating.
Believe it or not, foot candles are the most common unit of measure used by lighting professionals to calculate light levels in businesses and outdoor spaces. In a nutshell, a foot candle is a measurement of light intensity and is defined as the illuminance on a one-square foot surface from a uniform source of light.