The first Dark Shadows card series contained 66 cards and featured bright-pink borders. It was released by Philly Gum in 1968. Apparently the company rushed out their effort as quickly as they could (while the show's popularity was at its peak) because this is a frankly poor and bare-bones card issue. The card fronts showed a black-and-white photo still from the show, with a thin pink border and card number, but no caption; card backs contained puzzle pieces.
The second card series again contained 66 cards and was released in 1969. This series was a slightly more ambitious effort than the first. While the photos were again in black and white (the show had gone to color before the first card series had been released), they were surrounded by a wavy green border, with the card title in a bright pink block; the card number was prominently displayed at the lower left, with the copyright info along the bottom. The backs are, again, puzzle pieces.
Dark Shadows still enjoys a large fan base; between them and regular vintage trading-card collectors, these card series are expensive and difficult to complete.