The Giallo genre, a series of crime films popular in Italy from the '60s to the '70s, was on the wane in its native country. Dario Argento had made his start as a film maker with one only five years before (The Bird With the Crystal Plumage) and had contributed two more, neat and deadly entries. Whether he was wanting to revive the flagging genre or finish it off with a cinematic mountain, what he achieved was one of the most articulate and ranging examples of it with sumptuous sets, eyepopping kills, arresting music and solid central performances.
David Hemmings is paired with Daria Nicolodi (co-writer of the later Suspiria and future spouse of Argento) and they have a ball colliding with each other until the sparks turn into arc lighting. The closest Hemmings had come to the slapstick antics on screen here was the mime scene in Blow-Up. In Deep Red his character endures frequent indignities at the hands of the impossible new-feminist Gianna, her difficult car with the glove-box filled with airline booze bottles and whose power at arm wrestling leads to some hilarious embarrassment.
This plays against a frequently grim series of murders. No one in Gialli ever seems to get shot. They get decapitated, pierced by shards, knifed, sliced by sliding doors, alright, but I can only think of one case where a gun is used for a kill in the decades of the genre. The medium at the start is despatched by knife and then finished off with the glass of a broken window. There is death by boiling water, death by impact with a marble fireplace and a range of others as this high strung movie gets on with it.
Goblin's score tread a fine line between insistent electronic motive and outright prog rock. Both fit perfectly. There is also the eerie lullaby that plays over the mid credit sequence that pits the sharp violence against its disarming major/minor tonality. The motif was a direct influence on John Carpenter's theme for Halloween with its pressing grind and pealing piano figures.
As to plot, Gialli never boasted particularly tight examples, preferring to mix cultural shock value of "deviant" sexuality and decadence. Argento writes a coherent story and (you'll see this on a repeat viewing) plays fair by matching an early, easily missed detail, with a later revelation.
Now, all this gush aside, it should be noted that by current standards, Deep Red is a snail of a thriller. Personal investigation stories will, by necessity, have stretches in the middle act where everyone has to stop and take stock of the mystery and its dangers before racing to the finish but the Italian genre liked to ask its audiences in for a coffee or a drink, a red herring on toast and then a big finish followed by a coda no one saw coming. Deep Red's middle act is a lot of chemical bickering between the leads as the kill setups get more elaborate. This makes for a fascinating atmosphere but it doesn't hurry.
What it does do is widen the style, growing increasingly baroque in detail. The location of an old murder case that might be pertient is found through horticulture. A victim is distracted by the sight of one of the ghastliest walking puppets you are ever likely to see. He is a target because he discovers something hidden on a bathroom wall. When Mark discovers the child's horror drawing of the historical murder behind the plaster of an old house, he is led back to the scene to investigate a detail he missed only to discover an even more horrific scene.
All of this actually does add up. If his next film (Suspiria) threw narrative cogency out the window in favour of heavy violence and even more style, Deep Red plays like the highest that Giallo ever got as a rational film genre. I'm leaving out the treatment of the character Marco's gayness as it deserves more attention than I can give it, here. I will say that, along with other LGBTQ depictions in Argento's films, it is far too easy to characterise him as othering these characters in order to execute a Hollywood style punishment. It's not advocacy but it is live and let live. It wasn't all Fellini.
It is, as the saw goes, a pleasure to live at the beginning and end of an era. You could do worse, assuming you can find them (probably only on physical media now) than Deep Red be paired on a film night with Mario Bava's Blood and Black Lace. Both are strikingly visual and bracingly violent crime thrillers with aesthetic sensibilities more attuned to the realm of old master painters and Jacobean revenge playwrights than 20th century filmmakers. If that sounds good to you, track these down. You will be holding on to them, if you do.
Viewing notes: I watched Arrow Video's stunning 4K presentation of Deep Red in its extended cut. I could have chosen a 5.1 audio track in Italian of the cobbled English/Italian hybrid. This is a splicing of elements discovered long after the first edits were released, a reassembly that meant that a number of scenes suddenly go into an Italian dub. I have always found this easy to get used to and highlights David Hemmings' full performance (he dubbed his own part at the time). It's only offered in 2 channel but it's worth it.