Retrobright

Retrobright (stylized as retr0bright or Retrobrite^[1]) is a hydrogen peroxide-based process for removing yellowing from ABS plastics.

A TRS-80 Color Computer showing significant yellowing

The same computer after treatment, showing yellowing largely reversed

Yellowing in ABS plastic occurs when it is exposed to UV light or excessive heat, which causes photo-oxidation of polymers that breaks polymer chains and causes the plastic to yellow and become brittle.^[2]

History

One method of reversing the yellowed discoloration was first discovered in 2007 in a German retrocomputing forum,^[3] before spreading to an English blog where it was further detailed.^[4][5][6] The process has been continually refined since.^[1]

Composition

Retrobright consists of hydrogen peroxide, a small amount of the "active oxygen" laundry booster TAED as a catalyst, and a source of UV.^[7]

The optimum mixture and conditions for reversing yellowing of plastics:

• A hydrogen peroxide solution (oxygenated water).^[8] Hydrogen peroxide-based hair bleaching creams available at beauty supply stores can also be used, and are viscous, allowing them to be applied with less waste (especially to large pieces such as computer panels or monitors).^[9][10] The cream must be carefully applied and wrapped evenly with plastic wrap to avoid streaks in the final product.^[11]
• A source of ultraviolet light,^[8] from sunlight or a UV lamp.^[7]

Xanthan gum or arrowroot can be added to the solution, creating an easier-to-apply gel.^{[citation needed]}

Alternatives

Sodium percarbonate may also be used by dissolving it in water and following the usual steps for hydrogen peroxide, as it is sodium carbonate and hydrogen peroxide in a crystalline form.^[8]

Ozone gas can also be used for retrobrighting, as long as an ozone generator, a suitable container of sufficient size and a source of UV are available, but can take longer than other methods.^[8]

Effectiveness

The long-term effectiveness of these techniques is unclear. Some have discovered the yellowing reappears, and there are concerns that the process weakens and only bleaches the already damaged plastic.^[12][13][14]

Similar processes

The usage has also expanded to other retro restoration applications, such as classic and collectible sneaker restoration, where it is referred to by collectors as "sole sauce".^[15]

References

1. Ángel Jiménez de Luis (May 25, 2010). "Retr0bright lava más blanco" [Retr0bright washes more white]. El Mundo. from the original on September 21, 2017. Retrieved September 21, 2017.
2. Yousif, E.; Haddad, R. (August 23, 2013). "Photodegradation and photostabilization of polymers, especially polystyrene: review". SpringerPlus. 2: 398. doi:10.1186/2193-1801-2-398. PMC 4320144. PMID 25674392.
3. "Forum64 — Restaurierung eines C-64G, oder das Gastgeschenk des DOC64". February 19, 2007. from the original on August 20, 2018. Retrieved August 21, 2018.
4. "The "Retr0bright" Project". July 28, 2010. from the original on September 4, 2010. Retrieved August 21, 2018.
5. Doctorow, Cory (March 2, 2009). "Open source computer polish: Retr0Brite". Boing Boing. from the original on September 21, 2017. Retrieved September 21, 2017.
6. Mossesgeld, Rico (July 28, 2010). "How To Restore Your Beige Retro Hardware". Tom's Guide. Tom's Hardware. from the original on August 20, 2018. Retrieved September 21, 2017.
7. Maushammer, John (March 2, 2009). "Un-Yellow Old Plastics – Retr0brite!". Make:. from the original on September 21, 2017. Retrieved September 21, 2017.
8. Murray, David (20 August 2017). "Adventures in Retrobrite - New techniques for restoring yellowed plastic!". YouTube. The 8-Bit Guy. from the original on 1 December 2019. Retrieved 26 November 2019.
9. Narcisse, Evan (September 24, 2014). "The Secret To Keeping Old Consoles Looking New? Hair Product". Kotaku. from the original on May 15, 2017. Retrieved September 21, 2017.
10. Murray, David (April 6, 2013). How to fix yellowed plastics on old computers!. The 8-Bit Guy. Archived from the original on 2021-12-15. Retrieved May 29, 2017.
11. "How Retrobright Works! - The Geek Pub". The Geek Pub. May 27, 2018. from the original on May 28, 2018. Retrieved May 27, 2018.
12. Stewart, Terry (January 17, 2013). "Retr0Bright (or RetroBright) treated plastics re-yellowing even with minimal light exposure?" (published January 15, 2013). from the original on September 6, 2017. Retrieved September 21, 2017.
13. Petersen, Anja Liss (January 19, 2011). "Afrensning af plast med RetrObright" [Plastic cleaning with RetrObright] (in Danish). from the original on April 2, 2015. Retrieved September 21, 2017.
14. Flood, David (April 14, 2018). "A Look into the Yellowing and Deyellowing of ABS Plastics". from the original on September 30, 2021. Retrieved September 30, 2021.
15. "How to Easily Restore Yellowed Shoes". Angelus Direct. Retrieved 2023-02-04.