Photometric observations of variable extragalactic sources, like the BL Lac objects, are important to construct their historical light curves and to study their behaviour on different time scales. In the recent years important results have been reached with the development of international collaborations (e.g. the project OJ 94, Sillanpaa et al. 1996), useful to fill the unavoidable observation gaps of a single observer. It is therefore important that homogeneous sets of photometric data be readily published to be accessible to all the researchers active in the field: it is the combination of several observational campaigns spanning a large time interval that will finally bring out a deeper scientific insight.
In this paper we present the results of CCD photometric observations of BL Lac covering a time range of more than two years, from August 1993 to January 1996. The majority of the observations was performed in summer 1995 after the discovery of broad emission lines (Vermeulen et al. 1995).