We report four colour CCD photometry and photoelectric photometry of 3C 345 taken in the spring of 1990. After an initial partial recovery from the minimum observed in 1989 which was, at that time, the deepest ever recorded, a very fast decline to even fainter levels was seen over ten days in May 1990, which was then followed by a further partial recovery. The observations reveal that the light curve at minimum is highly active, showing strong colour variations from night to night and suggestions of possible rapid photometric variations even on time scales as short as a few minutes. The continuum energy distribution flattens with decreasing brightness, at the same time, an increasing excess of emission is seen in the in window, probably due to the 3000 A bump observed in many high luminosity quasars.