Why Practical Gore Ages Better Than CGI Blood

The usual version of this argument is nostalgia with a beard on it — old thing good, new thing bad, and here is a photograph of Tom Savini holding a head. I want to make the harder version, because the harder version is actually true and it has a mechanism.

Practical gore ages better because it was photographed. That is the whole thesis and everything else is elaboration. A latex appliance sitting on an actor’s cheek is in the room. It obeys the same lens as the actor’s face — the same focal length, the same depth of field, the same falloff, the same slight softness at the edge of the frame that the anamorphic glass imposes. It is lit by the same instruments, so its speculars match. It is recorded onto the same emulsion, so it carries the same grain structure at the same density. The film stock does not know that one part of the frame is a person and another part is a bladder of methylcellulose. It treats them identically, because they are both light arriving at the same time through the same hole.

Digital blood is drawn onto a photograph. Every one of those properties — the lens, the light, the grain, the motion blur, the way an out-of-focus highlight blooms — has to be simulated and then matched to the plate, and matched well enough to survive a viewer who has spent their entire life learning what real light does. The compositor is being asked to recreate for free the thing that the camera did automatically for the rest of the frame. Sometimes they win. The failures look like blood in a different room.

Where the mismatch shows

Watch a digital squib carefully and you can usually name the tell within two frames.

The commonest is motion blur. A camera exposing at 1/48th of a second smears anything moving across the frame; a CG element rendered without a matched shutter reads as unnaturally crisp, and the eye clocks it as “sticker” before the brain can articulate why. The second is interaction: real blood wets things. It soaks into a shirt, changes the fabric’s specularity, darkens as it oxidises, drips at the wrong moments and gets in an actor’s eye so that they blink involuntarily — and that blink is a gift no animator can write. Digital blood tends to sit on surfaces because simulating absorption is expensive and nobody has the budget for it on a shot that lasts eleven frames.

The third and worst is the actor. Give a performer a squib and they flinch, because something just went off against their chest. Give a performer nothing and they have to act being shot, which is one of the hardest things in the job and which almost nobody does well. Everything a horror film gets from the performer’s calibration depends on there being something to calibrate against.

This is a variation on an argument I have made about what latex knows that pixels do not across effects generally. Blood is the acid test, because blood is the one substance every audience member has personally seen.

What blood is actually made of

The trade has a folklore worth knowing, because it undermines the naive version of my own argument in an instructive way.

Real blood photographs badly. It is much darker than people expect — closer to a deep brown-black than the pillar-box red the audience has in its head — and it goes tacky and brown within minutes under lights. So practical blood is a pigment engineered to read as blood to an audience that has been trained by other films, which means the whole craft is a chain of conventions rather than a chain of facts.

Psycho (1960) used Bosco chocolate syrup down the plughole because the film was black and white and syrup had the right viscosity and the right density on the negative. Everyone in that shower was chasing a grey value. The British theatre standard for decades was Kensington Gore, a commercially sold stage blood; the American film version has usually been corn syrup with red and a little blue or green to knock the orange out, thinned or thickened per shot, because a wound that runs and a wound that drips need different fluids. Dick Smith’s recipes became a kind of samizdat among effects kids in the 1970s.

For anything that needs to be viscous — the ropey, mucous stuff that makes body horror feel biological — the answer is methylcellulose, the same food thickener that turns up in ice cream. It is what makes slime hang. And once you know the shopping list, the argument shifts slightly: the reason this material ages well cannot be that it is correct, because it never was. It is that it was in the room. Corn syrup catches a key light the way a liquid catches a key light. It has weight, it obeys gravity at the right speed, and when it lands on a floor it splashes according to physics that nobody had to write.

That is the entire advantage, and it is enough.

The exhibits

The Thing (1982) is the ceiling and it is worth remembering how insane the production was. Rob Bottin was around twenty-two when he ran that effects unit and he was hospitalised for exhaustion before the end of the shoot; Stan Winston came in to handle the dog-kennel transformation because Bottin was finished. What is on screen has held for forty-plus years, and the reason is only partly the sculpting. It is Carpenter’s cutting: the creatures appear in flashes, in bad light, behind moving bodies, and the film never lets you assess one. It gives the practical effect exactly the conditions a practical effect wants.

An American Werewolf in London (1981) won Rick Baker the first Academy Award for makeup — the category was created for it, essentially — and the transformation still works because Landis makes the perverse choice to shoot it in a brightly lit living room. Full light, no cuts to hide in. It is a dare, and it holds. The Fly (1986) got Chris Walas the same Oscar five years later, and Cronenberg’s film survives as a love story told in meat because the decay is on Jeff Goldblum’s actual face, changing his actual performance — you can hear the appliances affecting his diction, and that impediment is characterisation.

Then the workshop tradition underneath all of it: Savini, Bottin, Baker, Winston and the maestros who ran those shops, and the demented outer edge where Peter Jackson’s Braindead burned through fake blood by the barrel for a lawnmower finale that remains the most sustained piece of splatter comedy ever attempted. Re-Animator, From Beyond, Society, Street Trash — an entire decade of films whose reputations rest on gags built in a garage by people in their twenties.

The case against myself, in three parts

Practical ages badly too. Savini’s blood in Dawn of the Dead (1978) is bright orange, and it looks like poster paint, because it was — the film was graded for a stock and a projection standard that no longer exists, and Savini has been candid that the colour was a compromise. It does not stop the film being a masterpiece, which rather undercuts the idea that photographic accuracy is what we are responding to. Fulci’s gore is often visibly a rubber head on a table. Herschell Gordon Lewis’s is a butcher’s offcuts. We forgive all of it.

CGI blood works when it declares itself. Kill Bill: Volume 1 (2003) has arterial geysers pitched at Shaw Brothers absurdity, and 300 (2006) renders its blood as ink on a comic page. Neither is trying to pass. An effect that announces it is a drawing cannot be caught out for looking like one, and that is a legitimate and durable aesthetic.

Digital removal is the invisible win. The best CG work in gore is taking things away — erasing a rig, removing a leg so a real actor can have a stump, extending a prosthetic. Nobody complains about the digital effects they cannot see, which means my whole argument is partly a survivorship bias about failures.

Where it landed

The market settled the question in a way that pleases me.

Damien Leone built the effects for Terrifier 2 (2022) himself and released a film that reportedly cost in the low hundreds of thousands and took over $15 million — a number achieved substantially because audiences told each other the gore was real enough to be unpleasant. Then Coralie Fargeat’s The Substance (2024) took a body-horror film with a prosthetics department led by Pierre-Olivier Persin all the way to an Academy Award for makeup and hairstyling, on material a studio would have digitised twenty years earlier. Fede Álvarez’s Evil Dead (2013) had already made the point commercially, dumping a reported fifty thousand gallons of fake blood on a hillside for its finale.

The reason is that the man in the suit was buried too early, and a generation of directors who grew up on those tapes worked out that a thing in the room gives the camera something to find. The Void (2016) is a whole film built as an argument for that proposition, and it is not a great film, and its creatures are better than those in things ten times its budget.

There is one more reason worth stating, and it is about the audience rather than the image. A practical effect is a record of labour. When you watch Bottin’s spider-head walk out of the room you are watching a thing that a group of people in a workshop in Los Angeles actually built and actually operated, badly, on wires, at four in the morning, and got one usable take out of. That knowledge changes what you are looking at. The shot contains a real event.

Put a real object under a real light and the camera will do most of the work for nothing. That is the deal cinema has offered since 1895, and nobody has yet renegotiated it.