Scroll sideways to see the right side of the card
When you open the card you find the ad for Underwater! in Superscope. It turns out that the film didn't make it to theatres by Christmas as announced, thus falling behind Vera Cruz. The Eastmancolor film used in the card has lost everything but the magenta dye layer. Actual Superscope anamorphic prints were made using Technicolor's dye transfer process, which helped hide film grain and improve contrast, but with film stocks in the early 1950s, film reviewers were not complimentary about the quality of the Superscope screen image.
The second strip of film showing the area used for the Superscope print was not actually part of the process, it's merely an illustration. Technicolor produced their printing matrices by direct optical printing through Superscope printer lenses from the Eastmancolor negative.