Good Friday is the most somber day of the Christian year.  It has only one theme and only one event in mind:  Jesus' death.  We will celebrate this day with a service of "Tenebrae."  The word "Tenebrae" is Latin for shadows.  The purpose of the service is to recreate the betrayal, abandonement, and agony of the events; and it is left unfinished, because the story isn't over until Easter Day.  This is not supposed to be a happy service, because the occasion is not happy.  There are as many candles as there are readings, plus the Christ Candle.  Each candle is extinguished, one at a time after each reading.  Then the Christ Candle is extinguished, leaving the congregation in near darkness---and near total devastation.  The chancel area is stripped of all color.  So everything in the chancel area is draped in black; then everything turns to white on Easter Sunday.