(More reducing substances react with F.S. leaving a brick red precipitation).
The deep blue solution is made by mixing 1 drop of Fehling solution 1 ("Fehling 1") and 1 drop  Fehling solution 2 ("Fehling 2").
              "Fehling 1": 0,7 g blue copper sulfate dissolved in 10 ml water.
              "Fehling 2": 3,4 g potassium sodium tartrate and 1.0 g NaOH in 10 ml water.