Fans think they've figured out reason why some celebrities refuse to sign autographs with blue pen

Online sleuths think they've worked out why some celebrities refuse to sign things with blue ink.

The Crown star Claire Foy set the internet ablaze late last year after a TikTok video of her went viral following a brief exchange with a fan.

The English actor was in New York when someone with a blue pen tried to get her to sign what looked to be a magazine cover.

"I don't do blue," Foy said in response as she proceeded to walk past them.

Confused, the fan said 'what?' as Foy doubled down on her sentiments and insisted that she doesn't 'do blue'.

People online were quick to question why Foy refused to sign with a blue pen, and dozens of people have since shared their theories.

One said: "Most celebrities and athletes are taught not to do blue ink cause you can scan and forge the signature on other things and sell them."

Echoing similar sentiments, another claimed that celebs like Foy won't use blue ink because it's used in computing scanning recognition to forge signatures.

Others suggested that it might just be a 'superstition' some stars have.

Backing one person's claims, basketball player Patrick Beverley previously explained on the The Pat Bev Podcast with Rone podcast that he was told to avoid using blue pen when signing fans' items.

The NBA star said: "I was taught, maybe after my third year that you’re not supposed to use a blue pen because they can use that signature and slap it on another jersey and sell that, but you can’t do that with a black pen or grey pen."

While many were seemingly pretty confident that Foy's reasoning was down to potential forgery, Christopher M. Naghibi, a banker and attorney, thinks this idea is outdated.

Speaking to TODAY, he explained: "The notion that blue ink can be forged more easily than black ink isn't necessarily accurate in the context of modern technology. It really stems from an old, outdated ideology."

According to Naghibi, blue ink in scanned or photocopied documents did not hold the same contrast as black ink did when copied - explaining why many organizations typically insist that you sign official documents using black ink.

However, with 'advancements in scanning and printing technology' this isn't as much as an issue anymore.

Naghibi further noted that both black and blue ink can be forged.

Who knows, maybe some people just prefer black ink for aesthetic reasons...