Continuity mistake: Over the course of many Dark Shadows episodes set in the year 1795, Countess Natalie Dupres' dark, distinct, three-dimensional facial mole changes sides from left jaw to right jaw, briefly vanishes altogether, then returns as a faint, painted beauty mark on her right jaw.
Continuity mistake: 1967: Barnabas selects a treasure from a jewelry chest while bad guy Jason spies on him through a window. Willie is supposed to put the chest away, but when Jason later breaks in to steal it, the chest is still sitting on the table in plain view, so Jason has to pretend not to notice it. The break-in scene is recapped the next day, only this time, the chest is no longer on the table.
Continuity mistake: The newly-cured Barnabas, wearing a red striped bathrobe, screams when Dr. Lang opens the drapes to let the sunlight in. When the same scene is recapped the next day, Barnabas is suddenly wearing a solid blue bathrobe.
Continuity mistake: 1967: "Dark Shadows"' taping schedule seldom permitted retakes. Consequently, hundreds of goofs ended up on the air. Perhaps the funniest of them all occurred in a scene inside the Collins mausoleum, where the late Louis Edmonds was supposed to say, "Some of my ancestors are buried here." What came out was "Some of my incestors are buried here." To his credit, Edmonds not only kept his cool, but laughed and corrected the mistake in character.
Answer: It's probably episode 193 (even though the slate at the beginning says 58). It's the episode with Sam demanding that Roger return his paintings. Three clues from the Dark Shadows Companion and from the comments of Kathryn Leigh Scott and Louis Edmonds all agree that 1) Scott is in the episode and is done for the day prior to Edmonds without his pants; 2) Edmonds is wearing a smoking jacket, and 3) Edmonds is leaning on the mantle (which is actually the cabinet where the liquor is, because the fireplace mantle is too high to lean on and the bench in front of it prevents getting too close to). There are several "breaks" in the lengthy scene where commercial were probably inserted, and all of the shots are above the waist. The previously mentioned episode 54 has Edmonds in a suit and Scott isn't in the episode; episode 54 doesn't have Edmonds or Scott; and episode 86 only has Edmonds in a suit.
Lou Edmonds was a consummate actor and would not forget that he had a lengthy scene to perform. Rather, in Episode 86, Edmonds more understandably forgot that he had to perform one last 15-second scene (a simple toast). He had removed his shoes and pants before he was reminded of the final, brief shot, and he hurried back to complete it.
Charles Austin Miller