Visitors to the normally entirely family-friendly (and even a little staid) Canberra Museum & Gallery (CMAG) will need to be 18 to cross the threshhold of the exhibition X-Rated – The Sex Industry In Canberra.

CMAG's director, Shane Breynard, says preparing to stage the exhibition has been an "interesting journey" for his institution.

Having what he calls this "sealed section, just like the ones you sometimes have in magazines" is almost unprecedented. He's known lots of instances of galleries or museums putting up notices warning that there's something challenging just around the corner, but that sealing off a whole space is rare.

As it is, no casual visitor to CMAG will stumble naively into X-Rated.

For a start it is discreetly arranged in its own, upstairs gallery.

Signs at the foot of the stairs and at lift doors will warn what potentially shocking things there are upstairs.

Elsewhere various uses of "frosted glass" and other barriers will mean that no one, inside the gallery or even stickybeaking at it from outside, will be able to get an accidental glimpse of the exhibition's sometimes blush-making contents.

Breynard says gallery staff may even, when in doubt, ask young-looking people for proof-of-age ID.

Why has CMAG gone to such trouble?

Breynard says that as well as the exhibition's sometimes unorthodox contents (for example there are some lurid DVD porn-video covers, some photographs of goose-pimpled porn stars being filmed in action outdoors in uncomfortable-looking Canberra locations, and a poster of Black Mountain Tower as a penis wearing a condom) CMAG is conscious of schoolchildren being important CMAG clients.

School groups come to CMAG. At least 20 are due to tour while X-Rated is on and he's written to 20 schools to assure them that the students, touring the unsealed sections of CMAG, simply cannot get an accidental glimpse of X-Rated.

He and the exhibition's curator, Rowan Henderson, are rather proud of X-Rated.

It looks at the (ongoing) history of sex work in the ACT but especially at the way in which, in the 1980s, Canberra and sex and video pornography became synonymous in the public mind. Wits and detractors called the nation's capital "Pornberra".

Pro-pornography and pro-censorship forces (the latter led by the Reverend Fred Nile and his evangelical Festival of Light) clashed repeatedly and colourfully.

Henderson explains that in the mid-1980s the ACT became the only place in Australia where the manufacture, sale and distribution of X-rated pornography was legal.

Pornmongers duly flocked to Canberra and at its peak the making and selling of video pornography was the ACT's fifth largest industry.

X-Rated - The Sex Industry In The ACT continues in its "sealed section" of the Canberra Museum & Gallery, Civic Square, until September 20.