Arrests in a String of High-Profile Old Master Forgeries
news.artnet.com
news.artnet.com
Forgery is also the reverse of perperuating high prices at the cost of authenticity - to the market usually and if indistinguishable from the original.
The point of making it obviously a copy is to have a clear defense of "obviously I wasn't trying to make a perfect copy" should it later be sold as authentic--as happened to the 'forger' in the Nova episode. He genuinely sold it as a copy; it was only after several more sales (to which he had no connection) that it was fraudulently sold as authentic.
I would suppose that the activity you describe would become illegal if you knowingly sell the paintings to someone who intends to fraudulently pass them off as the real pieces.
There's a great episode of Nova from 1991 called "The Fine Art of Faking It" [0] where they not only follow the case of a man convicted of forging prints, but they track down the German farmer who painted a copy of a Matthias Gruenwald painting that ended up being presented as the real thing to the Cleveland Museum of Art (who paid a million dollars for it). He really did just paint a copy and artificially age it for a couple thousand dollars for a friend down the road; it only sold as real after several more sales for increasing amounts. The farmer was never accused of wrongdoing.
The best part: they pay him the same amount to do it again, and he does, on camera, demonstrating everything he did to make it look authentically 400 years old (besides being an almost perfect copy of a Northern Renaissance master's painting). For example, to add cracks to the painting, he takes the canvas off the frame and rubs it back and forth on the corner of a table, then rubs a thin wash of brown paint over the whole thing.
[0] https://www.nytimes.com/1991/12/17/news/review-television-ho...