Lighting gels are essential for a cohesive video.
Lighting gels are essential for a cohesive video.

Proper lighting goes a long way towards selling your project to viewers. Dynamic lighting allows your visuals to tell a visually captivating story, elevating your production to an entirely new level. A great way to do this is through lighting gels.

What Gels Do

Lighting gels serve a number of purposes, but the ultimate goal of any gel is to change a light’s color temperature. Sadly, retinas and camera lenses don’t see color the same way. Thus, managing color temperature, so images on film look like we expect them to, is a tricky balance filmmakers have dealt with since the advent of motion pictures.

Gels let you tweak the color temperature on your lighting rigs to make them warmer (more yellow/orange light) or cooler (bluer tones) depending on the needs of your scene. Used properly, gels add more realism to your video while bringing in another level of visual detail to the story.

Used properly, gels add more realism to your video while bringing in another level of visual detail to the story.

Plus, if you’re using a green screen, there are also gels to limit color spill. To illustrate, spill happens when light bounces off your green (or blue) screen and splashes onto your subject or actors. While it may only be a hint of green, it makes your post-production work — keying out the green screen — much more difficult.

Consequently, gels alleviate this spill by keeping the light intensity down — a cheaper alternative to reflective panels and umbrellas. The can also balance out the greens/blues with counter colors to keep them from being noticeable on camera. While a little bit of a spill may not seem like a big deal on the set, it’s a massive headache in post-production.

Tinted lighting gels help set the mood for your video
Tinted lighting gels help set the mood for your video

Gels serve these very practical purposes, but they also allow you to get creative. More than balancing things, gels can drastically alter the overall color palette of your scenes. For example, say you’re recording a project with science fiction themes. Using deep blues/violets create a stark neon, cyberpunk feel to your scenes (e.g. Blade Runner 2049).

Moreover, viewers may not consciously recognize the lighting choices, but it’s another layer of immersion into your story. Similarly, using colored gels to highlight important character moments or emphasize emotional points allows you to visually tell a story beyond the dialog.

This is all true, even if you’ve made the jump to LED lights over tungsten. While many LED rigs have built-in color temperature options, gels are still your best option for stylized and natural looks. Even with the best LEDs, there are still plenty of situations where gels can more easily give you the results you need.

Types of Lighting Gels

There are different gels for different purposes. So, knowing what each gel does and the best time to use them is crucial to them being an effective part of your project. There are four main types:

CTO – Color Temperature Orange brings down the intensity of daylight by filtering out the blues on the spectrum. Where daylight is considered to be around 5600 Kelvin, CTO gels your lighting set up down to 3200K. This will closer match indoor lighting sources.

CTB – Color Temperature Blue is the opposite of CTO, used instead to give your tungsten lights a more “daylight” appearance. These are great for outdoor scenes, or anywhere you want to have natural/daylight lighting in place.

Minus Green – This Magenta gel strips out the green and gives off a more natural indoor light. If you find yourself filming inside offices with fluorescent lights, this is a must. Minus green also helps with green screen color spill.

ND – Neutral Density gels are all about controlling light intensity. They’re like sunglasses for your lights, pulling the brightness down without affecting the colors. Primarily, these are used for covering windows to block out the sun coming inside.

One Size Doesn’t Fit All

Gels are incredibly helpful, but like all things in video production, no single tool is perfect for every situation. All gels have multiple gradations to choose from and you may need to test a few before finding the right one for each scene.

Thankfully, gels are among some of the cheapest pieces of equipment you can purchase, with variety packs going anywhere between $15-$30. While some are more expensive depending on the size (Neutral Density especially), on the whole gels are relatively inexpensive and will last multiple shoots. Without price being a hindrance, there’s no reason to ignore the benefits of using gels for your lighting setups.

In the digital age it’s easy to fall into the, “we’ll fix it in post” trap for color correction. Yet, that’s a long and tedious process that often results in a compromise. Using gels properly can eliminate those headaches early on. Sure, they require a little more setup, but the time saved in post is more than worthwhile. Not to mention, you’ll get far more natural tones via gels on set than by trying to replicate them in the computer.

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Jordan Maison studied Post-Production and art in college and has plied that knowledge for various websites over the years. On top of this he's a writer with work seen in Videomaker, Pure Nintendo Magazine, Cinelinx, Star Wars, Guinness World Records, and an official artist for various Topps Trading Card licenses.

5 COMMENTS

  1. There are more than 100 gel colors, manufactured by several well known lighting companies. Ask for a swatch book (free) and discover the potential for using color in your shoots.

    CTO, CTB, etc., correct color; many gels enhance rather than correct. Strong color to highlight and supplement architectural features, for example, becomes a strong compositional element in any shot, very much like highlight and shadow become compositional elements in black and white film noir.

  2. I posted this in the forum too – but the basic premise of the article is a bit flawed, in my humble view. Here are my comments. I read with interest the article in the magazine I read online today.
    “Lighting gels serve a number of purposes, but the ultimate goal of any gel is to change a light’s color temperature.”

    Absolutely and utterly wrong!! They change the colour. They could change the colour temperature, as in the CTO, CTB gels talked about a bit later, but once you move from these few gels to the colours, then what they really do is take bites out of the rainbow spectrum that tries to pass through them. If you take out the green and blue, you get left with the red content. If you look at the hundreds of gels in a swatch book, you’ll see a graph showing where they work. You get great weird ones too – Lee 126, Mauve – it appears to be a very dark purple – but anything yellow in the image, like a banana turns red! If you stick a bit over the lens of your camera it can be very odd, and practically impossible to create as a colour tweak in the edit. Gel changes colour. It does it by subtraction, so it’s wasteful of light. Some dark blue gel – Congo 181 for instance, is so dark it lets less than 1% of the light through – the rest goes up in heat!

    Gels are designed for tungsten light sources, 3K or 3.2K. The manufacturers have produced a totally different range of gels for LED sources that give the same colour on the subject from white LED light. A piece of tungsten gel and the identical colour effect LED gel look totally different to the naked eye, holding them up to a light source. This is of course because light from a heated piece of metal filament has gentle peaks and troughs in the frequency response, while LEDs have very sharp and powerful spikes, with very large missing sections.

    If you make music videos, then gels have been your friend for years, now, far less so. I’m personally down to very few tungsten sources, and I’m saving hundreds a year in melted and faded bits of plastic film. I still buy CT gel- but be aware again that converting lights from colour to colour is more difficult that it appears. My own rule is to recolour the brightest light source. Trying to blue up a tungsten source to match daylight is often ineffective. After 93 million miles, the sun is still so bright even a 2K tungsten source hardly makes an impact. If the light from the sun comes through a window, then you can put CTO on the window and tint the sunlight an orange colour which lowers the apparent colour temperature of the sun. The light stays at 3 or 3.2K and you tell the camera that and all is well. If you have inside lighting and mix tungsten and discharge, then colour treat the HMI. If your brightest source is say a 1.2K Arri, but your other lights are LED panels, then CTB on the Arri may make it closer to the LED light, but many LEDs have varieties of white, so looking through t he camera carefully is important.
    “Gels alleviate this spill by keeping the light intensity down — a cheaper alternative to reflective panels and
    umbrellas.”
    Rubbish! I’ve no idea what the writer meant here. If you get spill from your green screen, then that is light landing on the subject that you don’t want – black wrap or light sources with barn doors or just better fixture focussing is the key here – dimming them to lower spill lowers the light you want. If you use a colour filter, light drops, but what colour? A gel that cuts green would work, so a magenta gel allows little green light through, but that would be ineffective landing on a green surface? Reflective panels and umbrellas soften light – what has that to do with colour? Towards the end, the writer starts to talk about changing colours for mood, which is of course their primary role. Colour and Colour correction are VERY different uses, and the article in the first section really confuses new readers.

    The article is essentially correct, but presented in a style that makes big statements that will confuse, then corrects them later.

    My first experience with gels was in the 70s and the damn things were fragile, short lasting as they faded quickly and expensive, I still have rolls and rolls in the store, and out of hundreds of colours available – colour correction is a very small number – a few blues, a few oranges, and then the ones to remove flu tube casts. The vast number are for colours – NOT colour temperatures. The best selling ones are NOT CT.

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