What Is an Acetate?

Acetates — sometimes called slates, dubplates, lacquers, or one-offs — were never intended for mass consumption. They are hand-cut, short-lifespan discs produced at mastering studios for two main purposes:

  • Reference lacquers: created so pressing plants and engineers could evaluate a cut before manufacturing vinyl.
  • DJ-only tools: cut so DJs could test unreleased or work-in-progress tracks in clubs months before commercial release.

At their core, acetates are effectively the same medium as a lacquer master — the lacquer-coated discs used in vinyl manufacturing. A lacquer master is typically larger in diameter and serves as the source from which metal stampers are created for commercial pressing. Acetates, by contrast, were cut in smaller quantities and intended for evaluation, private testing, or DJ use rather than mass production.

Before USB drives, before CDJs, even before CD-R burners were widely available, acetates were the only way to debut new music on the dancefloor. In the 1990s and early 2000s, especially within progressive house and trance, DJs relied heavily on these discs to share music privately and create highly individualized sets.

Acetates offer a rare glimpse into the creative and technological processes that shaped modern dance music — a physical connection to a time when unreleased tracks traveled hand-to-hand rather than as files or links.

Physical Characteristics

Acetates consist of a thin nitrocellulose lacquer coating applied over a rigid metal core, typically aluminum. Each disc is cut in real time on a precision lathe — most famously the Neumann VMS series — resulting in a heavier feel, a distinctive scent, and a surface that was never intended for long-term durability.

Unlike commercial vinyl, acetates were created as short-lifespan professional tools, meant for immediate evaluation or club use, not archival preservation.

Many discs originated from London-based mastering houses such as:

  • Tape To Tape
  • Masterpiece Mastering
  • Master Room
  • 777 Productions

…as well as numerous facilities in the United States and elsewhere.

Acetates are usually packaged in plain, generic sleeves and might have a simple company label glued to the center, handwritten track details, or sometimes no label at all. This utilitarian presentation is part of their charm and authenticity.

Care & Handling Guidelines

Playback

Every play of an acetate introduces audible degradation. To preserve the disc, limit playback to one high-quality digital transfer, using a light-tracking stylus (e.g., Audio-Technica MicroLine) and appropriate A-D conversion and recording software. Avoid recreational or repeated listening.

Physical Fragility

Acetates are far less forgiving than vinyl. Vinyl may flex; acetates do not. Dropping an acetate can cause the lacquer to crack or shatter. If the disc becomes warped, the aluminum core has likely bent; attempts to flatten it risk chipping, flaking, or delamination of the lacquer layer.

Cleaning

Wet cleaning of acetates is strongly discouraged for non-experts. Liquids — especially alcohol-based solutions or ultrasonic baths — can seep into the lacquer-metal interface, leading to irreversible separation (delamination). Even small amounts of residual moisture can cause long-term damage. Unless you have specific training in acetate conservation, avoid wet cleaning entirely.

Storage

Store acetates upright (not flat) and never stacked. Keep each disc in its original sleeve with a polypropylene outer protector, and avoid PVC sleeves entirely. Maintain a cool, stable, and dry environment, away from direct sunlight and heat sources.

Framing (Non-Destructive Display)

If you plan to frame an acetate, use only conservation-safe, reversible mounting methods. Do not glue, tape, or otherwise adhere the disc or sleeve to any surface, as this will permanently alter and devalue the artifact. Ensure that the acetate and its sleeve can be removed in the future for potential playback, inspection, or further preservation.

Legal Notice & Statement on Rarity

Copyright & Ownership

Ownership of a physical acetate does not grant any rights to the underlying musical work or sound recording. Those rights remain with the original writers, publishers, labels, or other rights holders. Uploading, streaming, or otherwise distributing recordings taken from an acetate without permission may infringe copyright and could expose you to legal claims for damages.

It must also be considered that, in many cases, unreleased material has remained unreleased for decades by deliberate choice. It is not the role of a later private purchaser of a rare disc to unilaterally decide that the time has come to make that material publicly available.

Public Sharing & Devaluation

While physically possessing a rare acetate featuring unreleased music is an achievement in itself, it can be tempting to act as an online “hero” and upload a transfer to YouTube, social media, streaming platforms, or file-sharing sites. acetates.org and RareSlate strongly advise against this.

Once audio enters the digital ecosystem, it can spread quickly and irreversibly. Even sharing a file with a small circle of friends may lead—intentionally or unintentionally—to wider leakage. In practice, “unsharing” a digital file is nearly impossible.

Public uploads also have a direct impact on the physical object: widely circulating a high-quality transfer will almost always devalue the acetate in your possession, and may also devalue other acetates held by artists, DJs, and fellow collectors. This is a collective harm, imposed on others who did not consent to that loss of rarity or provenance.

Private Sharing & Watermarking

If, despite these concerns, you choose to share recordings privately and cannot be dissuaded, acetates.org and RareSlate strongly recommend researching and implementing robust audio watermarking techniques. Properly embedded, inaudible watermarks can help trace the origin of a leak should a “private” recording eventually surface in the public domain, allowing you to identify and address the source of that breach of trust.

Respecting Legendary & Unreleased Works

Many unreleased tracks associated with acetates have achieved a kind of legendary status: they were pioneered by renowned DJs, featured in iconic mixes, and, in some cases, never appeared in any other context. Part of what makes these recordings so magical is precisely their inaccessibility and the mystery surrounding them.

Releasing such material into the public domain can, paradoxically, diminish that legacy. Once a track becomes “just another file” alongside countless others, it may lose the aura that kept it alive in the memories of listeners for decades. In some instances, even the original artists no longer possess their own reference copies; the remaining acetates are, quite literally, the last known links to that moment in musical history.

For these reasons, it is the considered view and mission of RareSlate (operator of acetates.org) that, in many cases, the most respectful way to honor truly legendary unreleased works is to preserve their present state of exclusivity, rather than to circulate them widely. This position is rooted not only in legal and economic realities, but in a deep respect for the culture, mythology, and lived memories that surround these recordings.

Nothing on this site constitutes legal advice. Collectors and rights holders should consult qualified legal counsel in their jurisdiction for guidance on copyright, licensing, and related matters.

Preservation Mission of acetates.org

acetates.org exists to:

  • document and educate the public on the role of acetates in electronic dance music,
  • provide preservation guidelines for collectors and institutions,
  • catalogue mastering houses, cutting techniques, and historical usage,
  • highlight cultural stories behind iconic acetates,
  • promote responsible stewardship of these fragile artifacts.

Our long-term goal is to become a comprehensive reference point for archivists, DJs, historians, and collectors worldwide.

This site is a public educational project of RareSlate™ — the archival and commercial division responsible for maintaining a significant private library of historically important acetates related to the evolution of progressive house, trance, and DJ culture. RareSlate serves as long-term caretaker, cataloguer, and preservation advocate for these unique artifacts.