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Type of phonograph record

An acetate disc (also known as a lacquer, test acetate, dubplate, or transcription disc) is a type of phonograph record generally used from the 1930s to the late 1950s for recording and broadcast purposes and sees limited use as of 2009. Despite their name, "acetate" discs do not contain any acetate. Lacquer coated discs are used for the production of records. Unlike ordinary vinyl records, which are quickly formed from lumps of plastic by a mass production molding process, a lacquer master or acetate (instantaneous record) is created by using a recording lathe to cut an audio signal modulated groove into its surface – a sequential operation requiring expensive, delicate equipment and expert skill for good results. In addition to their use in the creation of masters, lacquers were widely used for many purposes before magnetic tape recorders became common, and in the modern era they are used by dance music DJs. They were used in radio broadcasting to archive live broadcasts, pre record local programming, delay network feeds for broadcast at a later time, and provide programming "from home" on the Armed Forces Radio Network. They were used extensively in Jamaica by sound system operators in the late 1940s and 1950s. Acetates were often used as "demos" of new recordings by artists and record labels. Some acetates are highly prized for their rarity, especially when they contain unpublished material.

Despite their name, "acetate" discs do not contain any acetate. They consist of an aluminum disc with a coating of nitrocellulose lacquer with acetone added to make a varnish. Glass was often used for the substrate during World War II, when aluminium was in short supply. The production process results in a disc that is different in several ways from the vinyl records sold to customers at retail. Most noticeably, vinyl records are comparatively lightweight and flexible, while lacquers are rigid and considerably heavier because of their metal cores. Lacquers commonly come in three sizes: discs for singles and discs for albums as well as discs for LP references and for 10" master cuts. The record's sleeve is typically nothing more than a generic cover from the manufacturing company and the disc's label is similarly plain, containing only basic information about the content (title, artist, playing time, and so on), which is usually typed but may be hand written. Although once produced in a wide range of sizes (from less than to more than in diameter) and sometimes with glass core discs, the examples most commonly encountered today are in diameter. Blank discs were traditionally produced in several different grades, with the best and costliest grade featuring the sturdiest core, the thickest coating and the most perfectly flawless mirror like surfaces. These top quality blanks were intended for cutting the master discs that, once silver coated, would be electrodeposited with nickel in order to electroform parts used in making stampers (negative profile metal moulds) for pressing ordinary records. Lower quality blanks were considered adequate for non critical uses such as tests and demo discs. Lower grade blanks were formerly made for home use by amateurs and may be very thin and flexible, may have a cardboard rather than a metal or glass base, and may have noticeably dull or slightly orange peel textured surfaces. In addition to the usual central spindle hole, there is traditionally at least one drive hole in the label area, meant to be engaged by a special pin that prevents the disc from slipping on the turntable during the recording process if the lathe does not have a vacuum turntable. Drive holes are often hidden by labels applied after the recording was cut, but they can usually be detected by careful inspection of the label or by holding the disc up to a light bright enough to penetrate the labels. Drive holes are no longer standard on lacquer masters, only on "dubs", because the additional holes can interfere with the electroforming process and professional mastering lathes use vacuum turntables that hold the workpiece (lacquer disc) in place with suction. One pump usually provides suction for both the turntable and the chip tube that pulls away the fine string of nitrocellulose lacquer removed by the groove cutting stylus. Acetate discs are made for special purposes, almost never for sale to the general public. They can be played on any normal record player but will suffer from wear more quickly than vinyl, since the lacquer does not have the same properties as that of vinyl.

Acetates are usually made by dubbing from a master recording in another medium, such as magnetic tape. In the vinyl record manufacturing process, a lacquer master disc is cut and electroforming is used to make negative metal molds from it; certain molds are converted into stampers, can be used to press thousands of vinyl copies of the master. Within the vinyl record industry, lacquers, sometimes called 'acetates' or 'refs', are also used for evaluating the quality of the tape to disc transfer. They were once a favored medium for comparing different takes or mixes of a recording, and if pressed vinyl copies of an impending new release were not yet available, acetates were used for getting preview copies into the hands of important radio disc jockeys. Acetates were produced in very small quantities using elementary cutting machines. The majority of discs found on the market were not labelled or marked, as distributing studios would only at most have their name and address written on the disc. It was generally up to the recipients to write the song title or name of the artist onto the disc by hand. On February 6, 2020, news broke of a fire at the Apollo Masters manufacturing plant in Banning, California. The plant produces Lacquer discs used in vinyl production with the fire completely destroying the manufacturing facility. The manufacturing facility is one of only two in the world, the other being Public Record (the lacquers of which are labeled MDC – the name of their principal distributor, based in Japan). This led to industry experts fearing that the vinyl production supply chain would be put under stress with heavy demand and only one factory worldwide.

Lacquers were generally used from the 1930s to the late 1950s for recording and broadcast purposes and see limited use as of 2009. Lacquers have not always been used solely as a means of evaluating a tape to disc transfer or cutting the final master disc. They were used for many purposes before magnetic tape recorders became common, and in the modern era they are used by dance music DJs. They were used extensively in Jamaica by sound system operators in the late 1940s and 1950s. Acetates were often used as "demos" of new recordings by artists and record labels.

In preparation for a record pressing, acetates are used for quality control prior to the production of the stampers, from which retail copies of the record will be pressed. The purpose of the test acetate(s) (called, 'reference disks') in the mastering process is to allow the artist, producer, engineer, and other interested parties to check the quality of the tape to disc recording process and make any necessary changes to ensure that the audio fidelity of the master disc will be as close as possible to that of the original master tape. The actual stamper sets can be made either from oversized lacquers or from DMM blanks (see Direct Metal Mastering).

Before the introduction of magnetic tape for mastering, disc recording was done "live" (see direct to disc recording), although sometimes intermediate disc to disc editing procedures were involved. a rare one reached £77,500 at auction. An acetate from The Velvet Underground, containing music that would later appear on their first album The Velvet Underground & Nico, sold in 2006 for $25,200. An acetate of Elvis Presley's "That's All Right" sold for $82,393.60 in 2013. The only known copy of Presley's first recording—a 78 rpm acetate from 1953 featuring "My Happiness" backed with "That's When Your Heartaches Begin"—sold for $300,000 at a Graceland auction in 2015.