It's an 'insider' term used for Columbia label LPs that were issued from the mid-50s till about 1962 (the first Bob Dylan LP was among the last titles with this label variation). For pop and jazz LPs, the label was red, with three oval figures in black (like a simple depiction of a TV screen with two legs) on each side, i.e. west and east, with the word 'Columbia' in bold letters on the top. The oval images are referred to as 'eyes', hence the 6-eye label. Classical LPs had a brown or mauve colour.
They were replaced by what is known as the 2-eye label, which had only one 'eye' on each side, plus the words '360 sound' at the lower edge of the label. These carried on till about 1970-71, when they were replaced by the orange label, with the words CBS in multiples on the periphery.
6-eyes and 2-eyes are prized today, because the LPs were made of thick, heavy vinyl, and because they were part of a period when Columbia recording studios took great pains to produce excellent sounding records, mainly in an all-tube recording chain, with minimal miking. For jazz LPs especially, the 6-eyes are most sought after today.
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