Daniel Radcliffe's first post-Harry Potter movie was cut by six seconds in order to secure a 12A rating on release, as well as having its sound level reduced and colours darkened in some scenes.
Speaking to Mark Kermode and Simon Mayo's film review show on BBC Radio 5 Live, BBFC head of policy David Austin explained that the film was "too scary" for that certificate in its first-submitted form.
"We felt that it was just too intense, too scary for 12A and we gave it a 15," Austin said.
"That was disappointing to the distributor, having got a PG-13 in the United States... they asked us to look at possible cuts.
"We had a look to see if we could cut the film for a 12A audience. We concluded that we could, so the film has had a number of tweaks made to it by us to secure the 12A."
He explained: "There are two particular sequences that are very intense... these sequences we reduced in length by a few seconds because we felt they were too strong for 12-year-olds.
"Throughout the film we asked the company to tone down some of the sharper sounds during jump moments. The film makes very effective use of sound and that really added to the intensity and the scariness of the jump moments."
Austin added: "There are some moments - again jump moments - where faces will suddenly appear at a window.
"Sequences like that where the company with our agreement toned down the image so that shots are darkened so that the impact of the shots is reduced.
"When the company had made all those changes we felt that it was classifiable at 12A. It is still a scary film but not quite as intense as it had been when we originally saw it."
Radcliffe has said that children under the age of 12 should not watch The Woman in Black.
He later told Chris Evans's Breakfast Show on BBC Radio 2: "This film is rated 12A. If your child is under 12, I would think long and hard about taking them, maybe go and see it first.
"It's a scary movie and psychologically scary and it's very, very dark. I know people are kind of used to me saying that with Potter but I really mean it this time. It's very scary and psychological."
The BBFC was criticised last week for giving teen 1990s TV show The Secret World of Alex Mack a 15 certificate for its DVD release, citing "potentially dangerous behaviour that may be copied".
> Daniel Radcliffe: 'Woman in Black terrifying'
Watch Daniel Radcliffe talk about The Woman in Black below: