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.
The definition of a lumen is a measure of the total amount of visible light emitted by a source. It is a pretty complex equation to find out exactly how many lumens a flashlight is. Mathematics aside, the best way to think of lumens is to compare them to birthday candles. If you have 1 candle 1 foot away from your face, it emits the same amount of light as 1 lumen.