“When you have a popular item, everyone knows about it and wants a piece of the action,” said Karen Grant, vice president and global beauty analyst of the NPD Marketing Group, which conducts industry research. “Usually, mass market copies prestige because they follow the trend of the consumer. They look to see what’s hot and then blow it out to everyone.”

Temptalia, a popular reference Web site about beauty products, has for three years offered a “Dupe List” that uses reader feedback to compile a percentage similarity of, say, NARS Super Orgasm to Lancôme’s Shimmer Pink Pool (95 percent, according to its users). In December 2011, a budget beauty blog called Nouveau Cheap posted an examination of Urban Decay Naked Palette and a look-alike, Physicians Formula Shimmer Strips, that was so detailed it might have been conducted by a C.S.I. unit.

Naked Palette, a best seller at Sephora and elsewhere since it was introduced in 2010, is one of the most widely copied products on the market, according to a founding partner and the chief creative officer of Urban Decay, Wende Zomnir, who named Victoria’s Secret as an offender. “It had the same font and was called Naked Eye Kit instead of Naked,” Ms. Zomnir recalled of their version. “Copycatting takes business away from a company. You don’t have to rely on the success of what someone else has done. There is plenty of room for everyone to create their own.”

But there may be little new under the sun, at least so far as face paint is concerned.

The Nakeds trend began in 1989 at Revlon, said Ingrid Jackel, the chief executive of Physicians Formula, referring to a line put out by Ultima II, then a subsidiary of Revlon. She said that there was little similarity between her company’s Shimmer Strips, which are inserted into their compact as one stick, and Urban Decay’s product, which is individually pressed and placed in the tin. And she pointed out that in 2003 when Urban Decay released a baked bronzer, Physicians Formula felt it was first with the product.