Cellophane let supermarkets sell meat by sight — self-service retail took off

When DuPont bought the US rights to cellophane in 1923, the transparent film had a flaw that blocked its biggest market: it was waterproof but not moisture-proof. Customers complained — candies stuck to it, knives rusted inside it, cigars dried out. DuPont hired William Hale Charch, a 27-year-old chemist, with a single assignment; within a year he had coated the film in micro-thin layers of nitrocellulose, wax, plasticiser and a blending agent, and sales took off.

The timing was perfect: in the 1930s supermarkets were abandoning counter service, and shoppers now chose goods off the shelf with their eyes. 'She buys meat with her eyes', ran a 1938 issue of The Progressive Grocer. Meat was the hardest case, because cut meat discolours fast — but a self-service meat counter could sell 30% more, so solutions appeared: pink-tinted lighting, antioxidant additives and an improved cellophane tuned to pass just the right amount of oxygen. By 1949 DuPont advertised the 'pleasing new way' to buy meat — pre-cut, weighed, priced and wrapped in the store.

The modern footnote is the paradox the film created. Multi-layer plastic packaging is hard to recycle, yet lighter non-recyclable wrap can generate less total waste than heavier recyclable packaging that never gets recycled. A UK supermarket that stripped all packaging from its fruit and vegetables saw its food wastage rate double; another, stung by criticism over plastic apple trays, sold them loose from boxes — and lost so many to transit damage that packaging per apple sold went up. Shrink-wrapped cucumbers keep 14 days instead of three.

Engineer the film itself — moisture-proof it, then tune its oxygen flow — and the see-through package solves retail's hardest self-service case: fresh meat.

The moisture-proof coating turned a niche wrap into food-grade packaging, unlocking DuPont's real market.

Transparency plus hygiene let customers select food by sight, which is exactly what self-service retail requires.

Oxygen-calibrated film and pink lighting solved the one category — cut meat — where seeing the product seemed impossible.

The 30% sales uplift gave retailers a hard economic reason to redesign stores around packaged food.

The last obstacle to a new retail format is often a materials problem; solve that and the whole format flips — while the waste trade-offs it creates stay counterintuitive.

Cellophane was later overtaken by Dow Chemical's polyvinylidene chloride — an accidental Second World War discovery commercialised as Saran Wrap — and cling film is now usually low-density polyethylene. The waste trade-offs it embodied remain contested: less packaging can mean more spoiled food, and the arithmetic of which wins is rarely obvious.