Here comes the sun

By G.F. | LOS ANGELES

WHEN Jesse Genet was 16 she wanted to print a photo on a T-shirt. Nine years on, together with her partner, Stéphan Angoulvant, she is finally happy with the result. Their company, Lumi, produces an ultraviolet-activated dye, called Inkodye, that can be exposed in sunlight or under high-intensity UV lamps. It enables continuous-tone reproduction, like that found in photographs developed in darkrooms or made using so-called dye-sublimation printers.

First, you rub or roll the dye, made of similar components to those used in frequently laundered clothing like hospital uniforms, onto a surface. Then you place a negative, whether large-format photographic film or transparency material printed from an ink-jet printer, on top of the dye. Exposed to full sunlight for a few minutes—or longer, depending on the light intensity—the sun-dappled portions become permanently fixed, whether onto a T-shirt, leather, wood or another material. A quick wash removes unused dye, which is water soluble and non-staining. (Get some on your fingers and walk into the sun, and the stain will persist, however.)

The process differs from two popular techniques for transferring graphics or image. Silk screening relies on a mesh covered with photo-sensitive emulsion which, similarly to Ms Genet's dye, hardens on exposure to UV light. But silkscreen cannot produce continuous tones. Instead, it uses coarse halftones, the Roy Lichtenstein-like patterns of dots, also found in newspapers and magazines, meant to fool the eye. The second method, dye sublimation, changes a dye from solid to gas and deposits it directly onto clothing fibres. It allows something close to continuous tones. However, dye sublimation requires lots of heat, and works only with polyester.

Silk screening was recommended to Ms Genet nine years ago at a local T-shirt shop, but she never felt it cut the mustard. After repeated attempts, which Ms Genet deemed unsatisfactory because the results did not live up to the image in her head, she was told by the shop's manager to give up and go away. But Ms Genet did not give up. A year later, after extensive research, she found what became the precursor to Inkodye: a chemical used in the 1950s that was no longer in production. An engineer had bought the rights together with the remaining stock and stashed it away for half a century. She tracked him down in his retirement, not far from her home in Michigan. "He told me I was a silly girl," Ms Genet recalls, and thought that she was wasting his time, her time and that of her stepfather, who would ferry her to meetings. She eventually wore down the owner and, with Mr Angoulvant, bought out his rights and stock three years ago.

The pair, who met while both attended the Art College Centre of Design in California, used the dye to experiment and create art projects, including a big early Kickstarter campaign to create wallets and other goods decorated by the process. (They raised $13,600 against a goal of $10,000.) They lived at The Brewery, a complex of living and working spaces for artists near downtown Los Angeles, where they still maintain their production offices. Over the following years they revamped the dye's formula to remove the original's toxic components, while retaining its light-fastness and solubility. They paid a fellow Brewery resident $50 a month to use a clotheswasher in a room with a tiled floor to make it easier to clean up.

A second crowdfunding project, completed last July, raised $268,000, more than five times the $50,000 goal. It allowed them to ramp up production of their dye, now called Inkodye. The benefactors received a kit of red, orange and blue dye (enough in the right hands to create artificial full-colour images), photocopier-compatible films and a mild detergent. An app helps invert images to the negative, as required. An update due in a few weeks includes augmented-reality features: point a smartphone's camera at a piece of clothing and see how an image would appear.

Ms Genet and Mr Angoulvant demonstrated the process on a blindingly bright Los Angeles day. The dye darkened in minutes. Ms Genet also showed off a remarkable machine, built with her stepfather, full of high-intensity xenon arc lamps. Their UV light exposes large projects, such as leather for furniture and outsized prints. And, of course, Ms Genet has her perfect print T-shirt at last. She also has a nifty product, a company—and a bright future.