More than 50 percent of Google searches today in beauty are about hair,” Mr. Balooch explained.

Mr. Balooch said the brush uses a combination of synthetic fibersThat mimic $200 to $300 brushes on the market.”

Mr. Balooch’s work impressed the L’Oréal brass, who in 2008 asked him to join the company’s research and innovation team, and build relationships with start-ups and universities.

Introduced in May 2014, the virtual makeup app relies on augmented reality technology, in which graphics are superimposed onto real-world imagery, to let users try on various shades of L’Oréal cosmetics before buying.

Mr. Balooch said he tried to make the app, which boasts more than 17 million downloads, in-house until perfecting the feature that distinguished Makeup Genius from other such apps proved a formidable challenge.

Le Teint Particulier, introduced in 2015 in two Nordstrom locations and scheduled to be rolled out globally this year, isn’t the first custom foundation on the market, but Mr. Balooch contends that it is the most accurate.

To demonstrate how easy it is to use, Mr. Balooch peeled off the back of one sticker it measures about one inch and is half the thickness of a strand of hair and affixed it to his left hand.