Hamburg’s archive of early TV recordings has yielded up stronger productions of 20th-century work (the Wozzeck, Globolinks and Devils of Loudun) than of classics such as Freischütz and Meistersinger. This 1968 Fidelio does not buck the trend, despite casting in strength right down to the role of Second Prisoner. You can almost feel the thin walls of these 18th-century prison settings vibrate as the performers walk by them. Production, as such, consists of heading downstage as soon as possible and staring directly into camera, the televisual equivalent of old-fashioned stand-and-deliver. Costumes, made with an evident eye on budget, are undistinguished in cut and colour, and worn freshly laundered from the peg.

The general dramatic stasis – and necessity of miming to a pre-recorded soundtrack – dampens even such performing talents as Lucia Popp and Erwin Wohlfahrt (a harrowing Mime for Wieland Wagner at the time of this filming). The sincerity and pain of Cassilly’s Florestan at least show through, but Silja’s normally electrifying Leonore (complete with trademark whip-off of cap to reveal her mane of red hair in the Dungeon scene) is muted, miscalculatedly over-internalised. Her singing, steadier, even more beautiful than has often been caught on recordings, offers some compensation. Only Theo Adam’s immensely frightening Pizarro, with (I suspect) influence from the concentrated minimalism taught him in Bayreuth, achieves an interpretation which reaches out to the viewer through the banal conventions of the filming.

But perhaps it was all just a bad day when the cameras rolled. The soundtrack is strong, Ludwig and his orchestra really involved from the Overture on, with especial sensitivity to Beethoven’s many pianissimi and wind and brass detail. From the technical viewpoint, all seems to have been restored as well as possible, but the end result is little more thrilling than collecting animated costume photos of the singers involved.