Bullet hit squib
A bullet hit squib or a blood squib is a practical, pyrotechnic special effect device used to simulate the appearance of a person being shot and wounded in films, TV shows and theatre performances. This is achieved by detonating a small explosive hidden in the actor's clothing, bursting open a pre-scored hole and a packet of fake blood to create an aesthetic that filmmakers and audiences alike have become accustomed to associating with a gunshot wound.
The device comprises a squib with an integrated igniter or glow wire, a pack of simulant, a protective shield and padding attached to the actor's costume. It is connected to a battery and a remote, allowing the squib to be triggered by the actor or a crew member.
The effect is usually carried out with clothing instead of on bare skin to conceal the device. While the portrayal is not necessarily accurate and is exaggerated compared to real life, it is nevertheless a useful tool to illustrate the demise of a character.
Historical context, usage and development
From early to modern day use
Bullet hit squibs were first used in the film industry as early as 1943 in Bataan, as shown in the adjacent image, and 1955 in Pokolenie, with the latter using fake blood added in a condom and a squib, a technique still widely in use today. The use of squibs in filmmaking has become a widely accepted and well-established technique for creating convincing and realistic depictions of violence. This approach has been used in many classic films such as The Matrix, Goodfellas, and The Terminator.Despite advances in digital effects, practical squibs are still widely used due to their ability to produce authentic, in-camera effects that enhance the overall atmosphere and intensity of a scene. While CGI can be employed to augment or replace squib effects in certain situations, the physicality and immediacy of practical squibs continue to make them a valuable tool in special effects for film and television. Bullet hit squibs can also be used in first responder moulage training and music videos, for example 99 Problems.
Related advancements
The earliest patent related to the manufacturing and chemical composition of bullet hit squibs was submitted in 1991. Since then, from the 2000s, a number of notable design or manufacturing features have been patented. Advancements include specific methods and chemical compositions to manufacture the squibs themselves, such as without heavy metals; a wearable, reusable pneumatic system that eliminates the need for explosives by using compressed air to expel fake blood through a small outlet. Another design incorporates traditional squibs but is pre-manufactured and nearly fully assembled, reducing on-set assembly time. This standardised design, however, limits customisation in terms of blood volume, spray pattern, etc.Device and costume preparation and implementation
In film productions, multiple crew members, including pyrotechnicians and costume designers, work together to create realistic blood squib effects. Pyrotechnicians are responsible for building the squibs, while costume designers prepare multiple identical outfits for the actors. Collaboration among writers, directors, producers, and actors is essential for determining the number and placement of squibs, as well as costume design. Depending on the budget, productions typically use between three and six, and sometimes eight costumes to accommodate various takes, camera angles, out of sequence filming, dress rehearsals, backups and tests. This can become costly, especially for low-budget filmmakers, leading to trade-offs between the number of character deaths, takes, and the number of squibs used. An overview of the device and costume preparation is illustrated in the gallery below.Bullet hit squib device
The actual squib used in movies is a flat, disc-shaped explosive about 0.5–2 mm thick and weighing between 2 and 384 mg, with the most common variants at 0.5 and 1.0 grain of high explosive. For comparison, a low explosive party popper is approximately 0.25 grains, and a small firecracker is about 2.5 grains. These squibs are used to create both entry and exit wounds, often accompanied by 10–30 ml of fake blood, depending on the fabric's absorbency and the desired visual aesthetic.The assembled blood squib device is designed with a low profile to minimise bulge through the costume. Fake blood is typically filled in a small balloon, packet, or condom placed on the squib, followed by a grooved protective plate and padding. The assembly is secured with duct tape, leaving a small front window for the simulant to burst through. Various simulants, such as fake blood, water, glycerine, or dry substances like dust and feathers, are used depending on the desired effect. Solid material can also be mixed with liquid simulants, such as cotton or meat, to provide solid texture to the visual effect. A bullet hit squib assembly weighs approximately 50 g, measuring 100x50 mm in length and width and 25 mm thick. Aligning the bottom half of the blood packet with the squib produces an aerosolised burst followed by a stream of fake blood.
Costume considerations for blood squib effects
modified for actors playing characters killed on screen are modified to conceal special effects equipment such as squibs and wiring, such as the holed and bloodied scrub top shown in the adjacent image. When preparing these costumes, considerations include script and scene requirements, how easily squibs can be integrated, aesthetics, lighting conditions and budget constraints. As a result, they play an important role as a figurative canvas, portraying violence and death through bursts of blood, frayed bullet holes and the stains. For gunshot wounds depicted on bare skin, prosthetics may be used instead. Several "distress doubles" or "stunt" costumes with pre-scored bullet holes are usually prepared for main characters to accommodate multiple takes and camera angles. These copies may be a size or two larger to cover for the additional equipment and padding. Additionally, a "hero" costume is used for earlier scenes and close-ups without squibs.Preparation and integration
Squibs are discreetly integrated into costumes to minimise visibility on screen, with examples shown in the gallery beneath. The fabric is intentionally weakened using techniques such as cutting, sanding, scoring, grating or plunging a scoring tool producing a crosshatch pattern, often required by health and safety legislation and loosely glued or taped back together. Small incisions in the fabric without actually cutting through it can reduce the visibility of scoring marks. Squib placement is kept consistent across all stunt costumes. To ensure that the fake blood is propelled outwards, squibs are aligned with precut bullet holes and securely attached. They are connected to a wired or wireless trigger, power source, and sometimes a programmable controller for synchronisation. The electronics can be placed within the costume or off-camera. Test fires and rehearsals are performed to check for faults and to make adjustments to timing or the amount of fake blood as needed.While most outfits can only be used once due to the destructive nature of squibs on the material, jackets and other durable clothing may be reused if the bullet holes are crosshatched in well-defined, clean-looking cuts. These garments can be wiped clean and reset for additional takes, such as the jacket in the main figure featuring pre-cut holes used for demonstrations. Other advantages include their ability to conceal devices, provide additional padding, support multiple squibs and be easily worn and removed, thereby minimising the risk of accidental premature rupturing. The main disadvantage of reusing jackets is that the reset requires more time between takes. Stronger fabrics may require more significant weakening or the use of a more powerful squib to ensure the bullet hole can be blown open, otherwise the squib may not rip up the fabric at all or in such a way that does not resemble a bullet hole.
During filming
Depending on the availability of hero and stunt costumes, the scene's length and the actor's comfort, the prepared outfit may be worn just before the shot, throughout a scene, or even for the entire day. However, it is advisable to minimise the time spent in the stunt costume to avoid accidental damage to the squibs, such as sitting against a chair with back squibs or spilling liquids that could affect the costume or the equipment.Once a take is successful, the wardrobe department photographs the "aftermath" to maintain continuity and prepares for the next take, scene, or clean up, or saves them for reshoots. In some cases, bullet holes may be enhanced for subsequent scenes. Costumes modified with squibs are not usually returned to the costume shop due to the irreversible damage caused by the pre-scoring on the fabric and the modifications inside.
Post-production
In post-production, techniques are often used to minimise the visibility of squibs and fabric scoring. Footage may be cut just before the squibs are triggered, or the use of digital editing tools such as reference frames and content-aware fill are also possible to some extent. Additionally, sound design further enhances the impact of gunshot effects.Production costs for bullet hit squibs
The making of bullet hit squib effects involves several expenses, including raw materials, labour, permits, and costumes. The primary component, squibs, generally cost between $20 and $60 each. Fully assembled devices – including fake blood, plastic packets, duct tape, wiring, and protective shields – can cost around $150. Preparing squibs for a shoot can require approximately 10–20 minutes per unit, an entire day for assembly and another day for costume setup, typically overseen by specialised pyrotechnicians who manage setup, testing, and detonation during filming.Costumes are another significant budget factor, especially with multiple outfits required to accommodate retakes. Using jackets shown on the right for a winter shootout scene as an example, with one reserved as the hero costume, one for testing, three for the stunt and another for dress rehearsal, totalling an estimated wardrobe budget of $3,000 at around $500 each without accounting for other wardrobe pieces. Fitting 30 squibs, or six each to the testing, stunt and dress rehearsal duplicates, would cost approximately $4,500, bringing the material costs alone for this stunt to approximately $7,500. In certain cases, selecting a more powerful squib allows costumes to omit the pre-scoring step, enabling unused costumes to be retained or refunded after filming.
Labour costs, including hiring technicians and obtaining location-based permits, further contribute to the budget. Rehearsals are sometimes conducted to acquaint with the effect and to speed up the filming process. The underlying cost of one take with ten squibs can be approximately $7,000 to $40,000 on set, excluding director, cinematography and talent.