Dancing the night away in a 1970s interior

This Agfacolor slide shows a typical domestic interior from the 1960/70s, with flowery carpet and chair covers and a very common decorative touch of wood panelling being used to create a 'feature wall' around the chimney breast. Under the window is another very popular item from that period - the radiogram. This was a unit which had a radio and a record player built into a cabinet with a good amplifier and set of speakers and provided, along with the television, the main entertainment in the house.

In this case, the main subjects of the picture are obviously taking advantage of the record which can be seen playing on the radiogram and are dancing.

From a photographic point of view there is movement shown in the picture and it doesn't seem to have the harsh shadows normally caused when a picture is lit by flash, so I wonder if this was taken in the available light on quite a slow shutter speed?