Multicolor photometry of SU UMa and U Gem during quiescence, outburst and superoutburst

The results of time-resolved observations of SU UMa and U Gem obtained over two-years are presented. Both stars are prototypes of different classes of dwarf novae. We studied brightness variations on different time scales: orbital, QPO and flickering. The multicolor BVRI photometry allows to distinguisch the geometrical and physical sources of these variations.