So we shared in a previous post, tips on how to use lighting to make your film look more cinematic. We noted that the main functions of lighting in filmmaking are to create separate, cast shadows and to fill. We also discussed how lighting can be used to enhance your film, create mood, tone, etc. and touched on why either hard or soft light is used in some scenes and subjects.
In today’s post, we will be discussing the types of light sources used in filmmaking, including the types of light equipment that is best suitable for scenes and subjects.
Over the years, different types of light have been invented to help improve and simulate mood, atmosphere, tone, etc. that a director wants to achieve for each scene during filmmaking. Anyone interested in lighting or cinematographer should be able to know, at the very minimum, the major types of these lights, their function and when to use which. And we think this article by Cinema 5d can help. The article highlights the most common types of lights used in filmmaking and gives a good explanation for each one including their pros and cons. We think it is worth the read for anyone interested in the subject. Combined with our previous article on lighting, you’ll be well on your way of mastering the theoretical aspect of lights and lighting in filmmaking after reading both articles.
Before delving into light sources, we would first discuss the basic, which basically is the terminologies that are commonly used while discussing light sources.
The basics
1. Practicals
A practical light is any light source that will appear in the scene such as a table lamp, any visible interior light sources, even a handheld flashlight. Often existing bulbs are swapped out for those of different wattage or colour temperature depending on the needed effect and desired contrast ratios within the scene.
2. Fresnel
A Fresnel lens is a special type of lens that is divided into concentric circles, resulting in a much thinner lens than a conventional lens of the same power. This lens evens out the light and allows for the beam to be varied from flood to spot by changing the distance between the lamp/reflector unit and the lens.
3. Performance Factors
- CRI
CRI stands for Color Rendering Index. It refers to the ability of a light source to properly and faithfully reveal the colour of an object compared to an ideal or natural light source. The highest possible CRI is 100 and is attributed to a perfect black body (a tungsten light source is a perfect black body, as is the sun).
- Colour temperature
Colour temperature refers to the colour” of white light emitted by a light source based on that radiated by a perfect black body at a given temperature measured in degrees Kelvin (K).
White light can be warm (yellow/orange) or cool (blue) and our eyes automatically adjust. However, the colour temperature of light sources and especially the mixing of different colour temperatures becomes very important when designing film lighting.
- Temperature Source
1,700 K: Match flame
1,850 K: Candle flame, sunset/sunrise
2,700–3,300 K: Incandescent lamps
4,100–4,150 K: Moonlight
5,000 K: Horizon daylight
5,500–6,000 K: Vertical daylight
6,500 K: Daylight, overcast
15,000–27,000 K Clear blue poleward sky
4 major types of light used in filmmaking
1. HMI
HMI means hydrargyrum medium-arc iodide, which is a metal-halide gas discharge medium arc-length lamp.
HMIs are most times used for high output (when required) and for recreating or augmenting sunlight interiors or exteriors too. It can be used to light up large areas as they have higher efficiency than incandescent lights. They produce 6000K colour temperature light that closely matches natural sunlight.
However, they are relatively expensive and have a high power requirement. Dimming is possible only to about 50% and the colour temperature increases in conjunction with dimming, thus creating a bluer light. If an HMI bulb falls while lit, it can explode and release a super hot quartz glass and mercury vapour. They also require an external ballast for arc ignition (up to 70,000 volts).
2. LED
LED stands for Light Emitting Diode. It is a solid-state semiconductor device. LEDs are perceived to be extremely efficient but are still limited in overall light sources. They produce only a single wavelength of light, which is why they are naturally monochromatic. Creating a full spectrum of white light has been the challenge of LEDs. This is achieved in one of two ways by either combining red, green and blue emitting LEDs or with white LED’s whereby the visible white light is created by phosphors that are excited by an ultra-violet emitting LED.
LEDs have been found to be used quite extensively in film productions. They are easily powered by battery thereby making it portable and does not require separate ballasts or heavy cabling. And to add more light, LEDs can also power more traditional fresnel style lamp heads such as the Arri L-series. They are soft even when lighting and they produce pure light without UV-artifacts.
An LED is extremely efficient: it has low power consumption and as stated above, it can be battery powered. It has a long life span and is excellent in timing by means of pulse width modulation control. LEDs are environmentally friendly, highly insensitive to shock and there isn’t any risk of explosion.
Their main disadvantage is related to their very high cost and they are currently still expensive vis-a-vis their light output.
3. Fluorescent
These are lamps that use the excitement of pressure mercury vapour to produce ultraviolet light. They are much more efficient than incandescent light and is capable of generating up to 100 lumens per watt which is similar to that of HMI. The spectrum light emitted depends on the mix of phosphors used and it is different from that of an incandescent source. A CRI (Colour Rendering Index) that is up to 99 can be achieved.
Fluorescent lighting is mostly used in fixtures containing banks and tubes and these tubes are either tungsten or daylight colour balanced. They produce a soft and even light and it can also be used in relatively close proximity to the subject. It is mainly used to light interiors and it has a better advantage of being more compact and cooler in operation than Tungsten and HMI. They can be used with low electric power.
Fluorescent light is costly but the lamp lasts long. It is cool and lightweight snd it is still capable of being soft even if lighting over a large area. However, fluorescent have been known to have flicker problem especially with domestic fluorescent installations not intended for photographic use. And fluorescent lights for film use have a high CRI while domestic tubes have a far lower CRI and poor colour rendition.
4. Tungsten
These type of light sources are related to the same type of incandescent filament bulbs, which become common in homes and offices. The halogen gas that is pressurised inside the bulb helps redeposit evaporated tungsten metal back onto the filament. Lighting fixtures can be faced or fresnel up to about 20KW in power and they are dimmable. They can produce a continuous spectrum of light from near ultraviolet to infrared, thereby producing a near perfect colour rendition. Also, when dimmed, it becomes warmer in colour meaning gels are needed to correct the colour temperature. They are basically used for interiors as they match the warm colours associated with domestic incandescent lighting. They do not use mercury like CFLs that are found in fluorescent or mercury vapour lights. They last longer than the conventional incandescent and they are instant in getting to full brightness, no warm-up time needed and they are dimmable. However, they can be extremely hot and consume lots of power. They are quite sensitive to oils and cannot be touched. When the bulb explodes (which happens sometimes), it fires out hot glass shards outside though a screen or layer of glass on the outside of the lamp can protect users.
13 thoughts on “4 major types of light sources used in film production”