This is definitely some bleak footage, this "Doin' Time," which brings us life as lived by the inmates of the Maryland House of Corrections at Jessup, tonight at 9 on Channel 7.

Prison is one of those natural subjects like hookers or proverty that get done and done because there's no end to the problem, no solutions, and no end of our interest in them, for good reasons and bad.

This time out, we get an hour-long tour of the prison, which is actually a month's worth of footage edited to show the strip searches, the isolation cells and the prisoners holding mirrors outside the bars to get a glimpse down the tiers. There are interviews, there's a man who staggers into the prison hospital covered with blood, there are Muslims praying, walls papered with magazine nudes and a guy playing "Amazing Grace" on the harmonica. The idea here is to show life as it's lived on the inside.

Prison as a subject has its lurid aspects: the violence, homosexuality and that punk, dead-end, homemade-tattoo badness that frightens you even while you're laughing at it.

And there's always some hope that we can change the system if we get sufficiently outraged, the key word being "always," because that's how long it's been going on, which is to say since the Quakers, of all people, invented the idea of penitentiaries around the end of the 18th century, as a rational substitute for hanging, flogging, branding and so on.

And there's our moral and civic duty to know about these places, to see how our fellow citizens, such as the ones on view here, get 70-stitch zippers slashed into their sides with razors; and go crazy and eat feces and smash up cells; and spend years doing nothing, a lot of them . .fs. nothing . . . no work, no school, nothing.

And we can sit there in front of the tube and be hard about it, and repeat the old line that "if you can't do the time, don't do the crime."

Or if you do the crime, try to do the time someplace else. Jessup, known among prisoners as "The Cut," was built before the Civil War to house 1,300 men. There are 2,000 there now. Then again, what's the last time you heard about an underpopulated prison? You get a prison decent enough to live in, and the taxpayers start calling it a country club, and they get upset if anyone beneath the rank of governor or attorney general does time in it.

Consequently, the problem stays with us, and people like cinematographer Paul Fine, reporter Ed Turney and sound engineer Clyde Rolley go out to Jessup and stay for a month to tell the rest of us about it, the relentless, unraveled mess that life becomes in prison.

They did a good job. At the end of it you'll feel depressed or sanctimonious or alarmed or thrilled or whatever it is that you feel in the presence of prisons; and you're apt to feel it more than usual. There's a good eye behind the camera, and a relentless quality to Holly Fine's editing.

The footage proves what an old-timer says at the start of the hour: "You can't have a good day in jail."