It recorded sound by "pressing" grooves into soft vinyl discs.
A million of vinyl discs were sold out for just a year.
The stampers are then used to mold the final vinyl discs.
In this way several million vinyl discs can be produced from a single lacquer original.
This reflected the title: a "clear" cover with the black vinyl disc as a visible "spot."
Customers who complained were sent the black vinyl disc free, and got to keep the picture disc as well.
Half a century later, when vinyl discs became the norm, there was another complication.
It was the first single to be released with one CD and two vinyl discs.
The standard one has two black vinyl discs with the second one being single sided.
A week later, on September 25, the album was released as a vinyl disc.