Films that take the audience inside Japan’s huge and diverse porn industry have been appearing for decades. In the 1991 “Skinless Night,” Rokuro Mochizuki told a semi-autobiographical story about a porn director’s desperation to escape the business (an aim that the widely praised film helped Mochizuki himself achieve). Last year, former pinku eiga (softcore adult film) director Ryuichi Hiroki featured a segment about a porn shoot in “Kabukicho Love Hotel,” referencing his own experiences.

Veteran AV (“adult video,” or hardcore) director Kei Morikawa has taken a fresh, briskly entertaining approach to this subject in his new film “Makeup Room.” Winner of the Grand Prix in the Fantastic Off-Theater Competition of this year’s Yubari International Fantastic Film Festival, the film unfolds from beginning to end in a room where five actresses put on makeup prior to filming their latest AV epic.

Not a single scene shows tussling on the futon. Instead the focus is on the lives and personalities of the actresses in the present getting-ready-for-work moment, with the director and other male staff playing supporting roles. The film’s rock-solid center is the make-up artist, Kyoko (Aki Morita), who is genuinely sympathetic to her charges, while intently focused on hustling them out of the room looking good — at least until the camera rolls.

Her first two makeup subjects — Sugar (Mariko Sumiyoshi) and Saki (Kanami Osako) — arrive more or less on schedule, but the film’s star, Masami (Beni Ito), has gone missing. The reason: Her boyfriend has found out about her profession, meaning she has to deal with the problem, if not ditch the job. Naturally, the already frazzled director (Kentaro Sakai) panics. Fortunately, two other actresses arrive: Masako (Nanami Kawakami), a voluble veteran back in the game after a sabbatical, and Matsuko (Lily Kuribayashi), a nervous newcomer who is about to make her AV acting debut. Finally, Masami saunters in — and promptly nods off from a lack of sleep. Will this show ever get on the road?

“Makeup Room” began life as a stage play, scripted by Morikawa, and requires the cast to actually act, which they do with a facility surprising given the minimal thespian skills typically required by AV films.

The stand-out, however, is non-AV actress Aki Morita, whose Kyoko is something of a lip-gloss-wielding saint (and is based on a real-life industry legend, who passed away before the “Makeup Room” shoot began). Minus her steady hand and calming presence, it’s easy to imagine the film’s AV shoot quickly dissolving into chaos.

At the same time, “Makeup Room” has none of the seedy look and gamy atmosphere of the stereotypical porn film. Yes, the five actresses are not starring in “Little Women,” but they are also hardly downtrodden sex workers. Instead they seem to enjoy the job to varying degrees, with the newcomer — having survived her baptism of fire (or rather, of bed) — the most enthusiastic.

Within the bubble of the AV world and this particular shoot, these women are the reasons everyone else gets paid — and they are deferred to accordingly. Also, whatever shame society attaches to what they do for a living no longer computes for them. While not wanting to advertise their work to their boyfriends, parents and former classmates, they do it with a certain elan. Victims they are not.

The film can be criticized for softening or eliding the darker side of the Japanese sex industry, but it also shows, with breezy humor and hard-earned insights, the human face of its workers that outsiders seldom see. With a few tweaks, in fact, it could be about many indie film shoots, from their razor-tight schedules to their semi-permanent state of crisis. As Benjamin Franklin once wrote in a different erotic context, “in the dark all cats are grey.” And film people are film people, made up or not.