Why are vinyl records black?
Think back to the first vinyl record you ever owned. Reverently sliding it out of its sleeve for the first time, taking care to only hold it by the edges so as not to damage it, admiring the ambient lighting dancing off of the delicately crafted grooves. Your first record is uniquely personal, varying in artist, genre, album artwork, title, theme, and countless other things that make it special to you. Chances are, one thing remains near-universal: that record is black.
Why is it that vinyl records are generally black? PVC (polyvinyl chloride), the material that vinyl records are made of, is clear in its natural form, allowing records to be manufactured in just about any color imaginable. Despite this endless array of choices, black is still overwhelmingly the most common option, leaving the burning question: why?
The Theories
A number of theories have been suggested, but each falls short of a satisfying explanation. One theory is that the carbon black material that provides a record’s pigmentation also increases its structural integrity. In the late 19th and early 20th century, manufacturers used shellac, a brittle resin-like substance produced by insects, to press their records. In order to ensure that the shellac held up, manufacturers would add ground up stone and carbon black powder to the mix in order to strengthen the otherwise brittle material. Of course, this is unnecessary in modern record pressing. Vinyl is tough enough on its own. And even if such supplements were necessary, there simply isn’t enough carbon black added to today’s records to make a difference on its own.
Another school of thought, also perhaps inspired by the origins of record pressing, is that the deep black color hides flaws in the vinyl. While this may have been necessary in the days of shellac records , modern technology allows for perfectly clear, defect-free records. Unlike when manufacturers pressed records with a mixture of shellac and ground-up stone, modern vinyl makers don’t need to worry about bits of bugs and dirt making it into the final product.
Still others think carbon black could reduce friction inside the groove and improve audio quality. Carbon is used as a dry lubricant in a variety of fields, but there is simply no documentation of such usage in records. This theory may have come from the fact that shellac records contained a small amount of other lubricants to ensure they released from the mold easily. One of the reasons that PVC is a perfect material for pressing records is its smoothness, which minimizes friction between the record grooves and the needle and eliminates the need for additional lubrication (although groove lubricant does exist).
The Electric Truth
While none of these popular theories hold up to scrutiny, Furnace Record Pressing Staff Engineer, Willem Ytsma, dug a little deeper to provide an explanation. Researching the pigmentation of records, Willem stumbled upon a patent for a conductive phonograph record, and in that patent lies the answer.
PVC is a natural insulator, meaning that it will build up a static charge over time as it’s handled and interacts with other objects. Due to the fact that static electricity attracts dust, that insulative property could be potentially disastrous for records. Any dust that accumulates in a record’s grooves will grind in between the needle and the groove wall when played, wearing down both the groove and the needle, and potentially even becoming permanently lodged in the wall.
Carbon has conductive properties, so adding it to the PVC increases the overall conductivity of the material, lessening the accumulation of static, and therefore, dust, on a record. By coloring records black with carbon-based pigment, manufacturers ensure their records last longer and sound better.
So if you ever pull out a record and someone asks about its color, you can tell them that is why records are black.
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