Through music, images, video and computing, plastic is ubiquitous as a data storage medium. From the first shellac record to the modern 4K Blu-ray, it has played an important role in bringing widespread media to the masses, and making modern computing what it is today.
Phonograph records
What is now colloquially known as a “vinyl” is more formally a phonograph or gramophone record, as it was originally made not of vinyl, but an early cellulose plastic known as shellac – a material that dates back as far as 1000 BCE. Shellac records were developed in 1894, quickly becoming an industry standard and going into mass production to replace the wax phonograph cylinders that audio was recorded on before.
RCA Victor introduced their vinyl-based Victrolac compound for records in 1931. Vinyl records have twice the groove density of shellac records with much improved sound quality. This demonstrated one of the first major consumer advantages of a synthetic polymer of a natural one. All records from 1940 onward were made of PVC, and still are to this day. PVC is ideal because its structure is anywhere between 10-20% crystalline, which makes it strong enough to support a groove being hollowed out of it and at the same time take a turntable’s stylus ploughing through without sustaining damage.
Magnetic tape - Compact cassettes and VHS
The Compact Cassette, also commonly called a cassette tape, is an analogue magnetic tape-recording format for audio recording and playback.
Compact Cassettes contain two miniature spools, between which the magnetically coated, polyester-type plastic film (magnetic tape) is passed and wound. These spools and their attendant parts are held inside a protective plastic shell. The tape is often either coated with a ferrite or chromium dioxide material. In the case of VHS, the tape spools are encased in a polypropylene shell to negate damage. Cassettes allowed audio recording, and most importantly portable music play in devices such as the Walkman and car stereos. Cassettes overtook vinyl in the 1980s and were replaced by CD in the 90s.
Cassettes, unlike records, allowed people the record their own audio at home. Be it with a Dictaphone, recording from the radio, illegal copying of cassettes or creation of mixtapes. This revolutionised music and led to the advent of music piracy.
Magnetic tape has the flaw of degradation of quality, beginning to degrade in 10-20 years, with experts estimating its lifespan to be no more than 30 years. This, alongside its habit of being “eaten” or “chewed” by the player, characterised by the magnetic tape being fed out through the bottom of the cassette and tangled in the mechanism of the player, means that cassettes cause a large-scale waste issue.
Floppy disks
Floppy discs owe their name to the fact that they were originally floppy. Originally produced by IBM and 8” in size, they shrank with technological advancements to 5.25” then 3.5”. The smallest floppy disk was actually only 3”, however the 3.5” became the predominant format, the only change being that the platter was developed further to hold more and more data over the years. The disk where the data is stored is made of plastic, coated with a magnetic medium so it could be read from and written to by a computer. The 3.5” floppy held 1.4 MB of data. A successor, the ZIP disk that could hold up to 100MB was released, however was largely overshadowed by the rise of optical media (CDs and DVDs).
Discs – CD, DVD and Blu-ray
The first music to be manufactured into a Compact Disc was the ABBA album ‘The Visitors’, first released in Japan in 1982. CDs gained huge popularity in the 1990s, outselling all other audio formats. By 2002, 200 billion CDs had been sold worldwide. However, in recent trends vinyl records have outsold CDs. Revenues from vinyl sales have been higher than CDs in the last few years, and in 2022 vinyl outsold CDs for the first time since 1987!
They typically hold up to 90 minutes of audio, encoded in a spiral track moulded into the polycarbonate layer with pits 500 nanometres (0.0005mm), and read with a laser that reflects off an aluminium layer. CD-Rs and CD-RWs are sold blank, so a CD recorder can change the colour of the discs’ photosensitive dye and write data to it. This dye layer isn't completely stable and can chemically break down over time, causing data loss. Also, the reflective layer on the top of the disc can oxidize, making the data difficult to read. CD-RWs use a metallic alloy instead of a dye, so are more durable.
As a result, many CD-R and DVD-Rs burned in the late '90s and early '00s are now unreadable in modern optical disc drives. And for those that remain, the clock is ticking. These issues are further exacerbated by high temperatures and humidities – making the attic, where the majority of them end up being stored, just about the worst place possible for them. This causes a potential waste issue, as the lifespan can be as low as 20 years.
Made similarly to CDs with injection moulded polycarbonate, Digital Versatile Discs offer significantly higher data density. As well as this can utilise an additional gold layer to the aluminium to store double the data – 8.5 GB instead of 4.7. The Assassin, Blade Runner, Eraser, and The Fugitive were the first movies on DVD, released exclusively in Japan on December 20, 1996.
Blu-ray represents the latest innovation over the DVD. Using a blue laser, data can be read from pits in the disc just 150 nanometres wide. Alongside a scratch resistant coating and the ability for up to 4 layer of recording, Blu-rays can hold between 25 and 128 GB of data, usually full HD or 4K video at 60 frames per second. Blu-ray is also responsible for the continuation of physical games media, as games got larger in file size the humble DVD was no longer enough, so many homes ended up with a home Blu-ray player in the form of a PlayStation 4 or Xbox One. In an era dominated by streaming, Blu-rays still have a place of value. For those who want to own their media definitively, or don’t want to splash out for that 4K Netflix plan to get the highest quality, Blu-rays are the answer.
There are many other formats that never made it big – such as Betamax, A VHS competitor, Laser Disc, which was simply too big, too expensive and couldn’t hold enough video to be viable. The players were especially expensive, and they also didn’t allow recording like VHS did. A format called HD DVD fought against Blu-ray but ultimately lost as the universal standard. Mini disk is another niche format that was basically a smaller CD, aimed at a portable use case. The Nintendo GameCube used a similar format for game storage, being based on the mini-DVD.