Red, Donmar, London<br/>Darker Shores, Hampstead, London<br/>1984, BAC, London

The colour of blood, the colour of money

Both men are sweating blood. Or has the artist’s studio turned into an abattoir? Played by a shorn-headed, bullish Alfred Molina, Mark Rothko is priming a huge canvas, together with his skinny young assistant, Ken (Eddie Redmayne).

They crouch, very still. Then in a frenzy they stab their brushes into buckets of gore-red paint, dart round each other, and drench the white cloth with bold strokes. When they fall away, panting, their faces are like gules-spattered masks, streaming vermilion. It's electrifying, as if they've been fighting some monster – or each other, minotaur and toreador.

They needed that, and so did this new American biodrama, Red, by John Logan (better known as the screenwriter of Gladiator and The Aviator). In its first scenes, Red sounds like an art lecture, and this play could really bomb in a B-rate production. "What do you see?" demands Rothko, before the newly hired Ken has stepped through the door of his spartan Manhattan workshop, circa 1958. "You've got to get close," he continues, dishing out instructions on how his masterpieces need to be viewed. "Let it pulsate. Let it work on you ... Let it spread out. Let it wrap its arms around you; let it embrace you ..." Ken gazes, dumbstruck, like a rabbit in headlights.

But this is a portrait of the revered abstract artist where fierce arguments and sharp criticisms come to the fore. Redmayne's Ken isn't as wide-eyed as he seems, and a generational battle develops, with Pop Art on the horizon. Settling in, Ken refuses to be cowed by Rothko's swingeing intellectual put-downs. He is prepared to gall the great man. Albeit with the ideas of a sophomore thesis, he compares Rothko's formal "Apollonian" art with the wilder, "Dionysian" Jackson Pollock. The underling also, climactically, sticks the knife in, puncturing his boss's self-belief, challenging his highbrow creed, questioning why he has accepted the lucrative Seagram Building commission to create an epic series of red-and-black murals, merely to adorn a ritzy restaurant.

Michael Grandage's production is thrilling, primarily because Molina and Redmayne quarrel over artistic principles with fiery tempers. They confess to inner demons – harrowing memories or depressive fears – but then gore each other anew. These excellent actors – like Rothko's paintings – also offer multilayered depictions. Redmayne shimmers with the nerves and stubbornness of youth, fondness and exasperation. Molina manages to be excoriating, laughably self-satisfied and a suicidal loner.

There's also the simple pleasure of watching Red as a work play. Redmayne hammers frames together, tips bags of pigment into old coffee jars and heats glue over a rusty gas ring. For each new scene, he and Molina hoist up – on a pulley – another of Rothko's glowering, Seagram Building series. These are splendid forgeries by set designer Christopher Oram. And, under Neil Austin's magical lighting, a hidden cadmium orange suddenly phosphoresces amid the coal black, like a door opening into a furnace. Well worth seeing.

That glow is also eerier than anything in Darker Shores, a supposedly spooky tale by Michael Punter. Funereal drapes engulf the haunted mansion where Tom Goodman-Hill's Professor Stokes is staying. Stokes is a Victorian professor of natural history who doesn't believe in ghosts. But he has lost his beloved wife and child some years back.

The poor devil is, duly, plagued by a bunch of unquiet spirits who clunk around in the attic and appear, as wobbly video visitations, outside his windows. The only intake of breath which Anthony Clark's production inspires is, alas, a yawn. Darker Shores is, fundamentally, just a load of simulacra, in the sense that it clumsily imitates others' vintage ghost stories.

Valiantly taking over from Mark Gatiss (who had to withdraw), Goodman-Hill relishes Stokes's florid pedantry, and Vinette Robinson copes admirably as the ghoul-possessed maidservant. Nonetheless, Julian Rhind-Tutt, as the American medium Beauregard, mainly sits slugging whisky, looking like a Byronic cowboy. He does a spot of prestidigitation and a table levitates, but one senses he'd rather pull off a wholesale vanishing trick.

The disappeared in George Orwell's 1984 are more politically worrying. Clerks like Winston Smith in the totalitarian Ministry of Truth, if suspected of "thoughtcrimes", are removed and written out of history, or brainwashed into toeing the party line. Disappointingly, Blind Summit's new adaptation of the novel – where flesh-and-blood performers mix with puppets – seems over-anxious about entertaining its audience. The merciless agent O'Brien – who Winston believes is a resistance leader, but ends up as his torturer – is played by Gergo Danka like Groucho Marx: a clown with buckled knees and a jutting belly. Director Mark Down doesn't seem to notice half his actors are pulling silly grimaces and shouting.

Still, others manage to steer a path between engaging naturalism and playfulness. Simon Scardifield's Winston has quiet defiance and gymnastic wit, enjoying expressionistic coitus with his illicit lover, suspended above her in a kind of flying handstand. The couple are always being snooped on, as the ensemble turn themselves into corridor walls or rustling forests, with just a handful of wooden chairs. And the deliberate blurring of indoctrinated citizens and puppets with corrugated cardboard heads is, ultimately, unnerving.

'Red' (0870 060 6624) to 6 Feb; 'Darker Shores' (020-7722 9301) to 16 Jan; '1984' (020-7223 2223) to 19 Jan