Bi-colour control and coloured gels solve different lighting problems.

A bi-colour LED lets you move through a range of white-light colour temperatures electronically. A gel physically filters that light to create a correction or colour that the CCT control alone cannot produce.

Used together, they give you a very flexible workflow: use the fixture to get close, then use the gel only when the scene needs something beyond tunable white.

Enrico Ripalti
About the author

Enrico Ripalti

Maxima Co-Founder · Creative Director at Cinestudio

Creative director and digital artist working across commercial filmmaking, photography and branded content. Enrico combines practical on-set experience with the development and real-world testing of professional lighting tools at Maxima.

What does a bi-colour control actually do?

A bi-colour fixture changes the white point of the source.

In practical terms, it lets you move between warmer and cooler white light, for example:

  • tungsten-oriented interiors;
  • neutral mixed environments;
  • daylight;
  • and changing natural-light conditions.

This is different from adding a coloured gel.

Changing from 3200K to 5600K still keeps the source fundamentally within the family of white light.

What does a gel do that bi-colour cannot?

A gel can modify the spectrum in ways that a Kelvin control cannot.

Depending on the gel, it can:

  • correct green or magenta contamination;
  • create a stylised colour;
  • match an unusual practical source;
  • push the source outside its normal CCT range;
  • or reproduce a specific environmental character.

That means gels remain useful even on modern tunable-white fixtures.

Do you still need CTO and CTB on a bi-colour fixture?

Much less often.

If your fixture already covers the white-light range you need, it is normally more efficient to make the adjustment electronically rather than placing a correction gel in front of the source.

That avoids unnecessary light loss and keeps the setup simpler.

For example, if you need to move from a daylight-oriented setting toward tungsten, and your fixture already covers that range, there is usually no reason to add a full CTO purely for correction.

When would CTO or CTB still make sense?

When you need to go beyond the available CCT range or create a specific relationship between sources.

You might deliberately:

  • push a daylight source even cooler;
  • create an exaggerated warm practical effect;
  • match a source that does not correspond neatly to the fixture’s Kelvin scale;
  • or combine a moderate electronic CCT adjustment with a lighter gel.

The gel becomes another creative variable rather than the only way to change colour temperature.

Why use the fixture first and the gel second?

Because gels absorb light.

The denser or more saturated the gel, the more output you lose.

If the fixture itself can perform most of the required correction electronically, you can then use a lighter gel for the remaining adjustment.

This usually means:

  • more output reaches the subject;
  • less heat is absorbed by the gel;
  • and the overall workflow stays simpler.

What are plus-green and minus-green gels for?

These are particularly useful in mixed-light environments.

Kelvin alone describes the warm-cool axis.

It does not fully describe green-magenta deviation.

That means two sources can have similar measured colour temperatures while still looking visibly different because one is slightly green or magenta.

Plus-green and minus-green gels allow you to correct that second axis.

Where is that useful in practice?

For example, when working with:

  • fluorescent practicals;
  • architectural LEDs;
  • older office lighting;
  • mixed commercial interiors;
  • or sources from different manufacturers.

A bi-colour fixture can bring you close on Kelvin, while a correction gel can help finish the match.

Can gels be used purely for creative colour?

Absolutely.

This is where they remain fun and extremely useful.

A tunable-white fixture can be transformed with:

  • straw;
  • lavender;
  • blue;
  • cyan;
  • red;
  • magenta;
  • or any number of theatrical and photographic gel colours.

The result is not the same workflow as using an RGB or RGBWW fixture, but it can be very effective.

Is bi-colour plus gels better than RGBWW?

Not universally.

They are different systems with different advantages.

An RGBWW fixture can offer:

  • rapid electronic colour changes;
  • animated effects;
  • remote colour control;
  • and a very large colour gamut without physical filters.

A bi-colour fixture with gels can offer:

  • a simpler white-light-oriented workflow;
  • high output from a dedicated white-light engine;
  • familiar physical correction tools;
  • and the ability to add colour only when required.

The correct choice depends on the production.

Why might a cinematographer still prefer gels?

Because gels are tangible and predictable.

Many cinematographers already understand exactly what a specific correction or effect gel does.

A gel can also be placed:

  • directly on the fixture;
  • on a frame;
  • only over part of a beam;
  • or farther away from the light.

That opens creative possibilities that are different from simply selecting a colour electronically.

Does the starting CCT affect the final colour through a gel?

Yes.

The gel is filtering whatever spectrum you feed into it.

A coloured gel over a 3200K source will not necessarily look identical to the same gel over a 5600K source.

This is one reason it is useful to think of the fixture setting and gel as a combined system.

Should you trust the gel name or number alone?

No.

Use it as a starting reference.

The final appearance depends on:

  • the source spectrum;
  • the selected CCT;
  • the gel itself;
  • the camera sensor;
  • white balance;
  • exposure;
  • and the surfaces being illuminated.

For critical work, test the actual combination on camera.

Do gels behave exactly the same on LED and tungsten?

No.

Different light sources have different spectral distributions.

A gel designed or traditionally used with tungsten may therefore produce a slightly different result when placed over an LED source.

This does not mean the gel is unusable.

It simply means the final colour should be evaluated rather than assumed.

Does a gel reduce CRI or TLCI?

Once you intentionally colour a source, CRI and TLCI become much less useful ways to describe the result.

Those metrics are designed primarily to evaluate white-light colour rendering against reference sources.

A deeply blue or red light is intentionally spectrally selective.

It would make little sense to expect it to reproduce all colours neutrally.

For effect lighting, the relevant question becomes whether the colour looks right for the image.

What about light loss?

Every gel absorbs part of the spectrum.

A light correction gel may produce modest loss.

A saturated effect gel can absorb a very large amount of output.

This matters especially when the light is:

  • far from the subject;
  • already passing through diffusion;
  • running from batteries;
  • or competing with strong ambient light.

Why source output matters when using gels

Higher fixture output gives you more freedom to spend light on filtration and diffusion.

If you begin with limited output and then add:

  • a saturated gel;
  • a softbox;
  • and perhaps another diffusion layer,

you may quickly lose the exposure headroom you need.

That is why gel work is not only about colour. It is also about energy management.

Can you stack gels?

Yes, but I would do it intentionally.

Stacking filters multiplies both the colour interaction and the transmission loss.

A correction gel plus diffusion is common.

Multiple colour-effect gels can produce interesting results, but they can also absorb so much of the spectrum that the source becomes inefficient.

Whenever possible, use the fixture’s CCT control to perform the broad white-light adjustment and reserve gels for what the fixture cannot do electronically.

Should gels go directly on the fixture?

That depends on the fixture and the gel.

Some systems use:

  • gel frames;
  • clips;
  • barn-door holders;
  • or separate diffusion frames.

Always keep the material within its intended operating conditions and follow the fixture and gel manufacturer’s guidance.

Why gel frames can be creatively useful

Placing a gel farther from the fixture lets you treat colour almost like another modifier.

You can cover:

  • the whole beam;
  • only part of the beam;
  • one edge;
  • or separate areas with different colours.

This can create layered effects that are harder to reproduce with a single electronically mixed colour.

Can bi-colour plus gels help match practical lights?

Yes, and this is probably one of the strongest technical uses.

Real-world practicals rarely sit at a perfect textbook colour temperature.

A lamp may be:

  • warm;
  • slightly green;
  • slightly magenta;
  • or spectrally unusual.

Bi-colour gets you close on the warm-cool axis.

Gels allow additional correction.

Why a colour meter can help

When matching sources precisely, a colour meter can show more than a simple Kelvin reading.

That is useful when deciding whether the remaining mismatch is actually a colour-temperature problem or a tint problem.

On smaller productions, a camera and calibrated monitor can also provide a useful practical reference.

Can you use gels to make bi-colour more cinematic?

I would avoid thinking of “cinematic” as a particular colour.

But gels can absolutely help create intentional colour relationships within a scene.

For example:

  • warm interior against cooler exterior;
  • cool moonlight against tungsten practicals;
  • a subtle straw key;
  • or coloured accents in the background.

The important thing is that the colour supports the visual idea.

Where Maxima Rapida fits

Maxima Rapida is particularly useful when this kind of work needs to happen on location.

Its 2600K to 6800K bi-colour range lets you perform a substantial amount of white-light adjustment before adding any physical filter.

Rapida also offers:

  • 23,000 lumens of output;
  • R9 97.1;
  • TLCI 98;
  • approximately 1.8 kg weight;
  • V-Mount battery operation;
  • and IP54 environmental protection.

The output headroom becomes useful when gels and diffusion begin absorbing light, while battery operation and IP54 protection make the fixture particularly practical for changing location conditions.

Where Maxima Spectra fits

Maxima Spectra offers the same broad 2600K to 6800K white-light range in a lighter 1.4 kg fixture.

Its built-in colour touchscreen makes CCT adjustment immediate, which is useful when experimenting with a physical gel and then fine-tuning the white-light foundation underneath it.

Spectra offers:

  • R9 97;
  • TLCI 98;
  • and compatibility with Profoto® and Bowens® light-shaping systems.

Why modifier compatibility matters for gel work

Gels are only one part of the optical chain.

The same shot may also require:

  • a reflector;
  • a softbox;
  • an umbrella;
  • a grid;
  • or a diffusion frame.

A modular point-source fixture lets you decide where the gel belongs within that system rather than forcing you into one fixed lighting architecture.

Should you buy RGBWW instead?

If your work regularly requires:

  • many saturated colours;
  • fast electronic hue changes;
  • animated colour effects;
  • or remote colour programming,

then RGBWW may be the more logical tool.

If most of your work is high-quality white light and colour is an occasional correction or creative requirement, a bi-colour fixture plus a small gel kit can remain a very effective approach.

Bi-colour and gels are complementary tools

That is the important takeaway.

Bi-colour control handles the white-light foundation quickly and electronically.

Gels extend that foundation into corrections and colours that Kelvin control cannot produce.

You do not need to choose one or the other.

The useful question is simply:

Can I create this colour more efficiently with the fixture, or does the scene actually need filtration?

If you are building a compact lighting kit and want to understand whether bi-colour, gels or a full-colour fixture makes more sense for the kind of productions you shoot, you can talk with a Maxima lighting specialist.

Tell us whether you mostly work with natural light, mixed interiors, commercial photography, interviews or narrative production. We can help you choose the simplest lighting workflow for the colours you actually need.

Talk with a specialist

Frequently Asked Questions

Do I still need CTO and CTB gels if my fixture is bi-colour?

Usually less often. If the required white-light correction is already inside the fixture’s CCT range, electronic adjustment is generally more efficient because it avoids the additional transmission loss of a correction gel. CTO and CTB remain useful when you want to move beyond the fixture’s range or create a specific effect.

Can plus-green and minus-green gels still be useful on bi-colour LEDs?

Yes. Bi-colour controls primarily adjust the warm-cool axis, while practical sources can also differ on the green-magenta axis. Plus-green and minus-green filters can therefore be useful when matching fluorescent, architectural or other artificial sources.

Is bi-colour plus gels better than RGBWW?

Not universally. RGBWW fixtures are valuable for rapid electronic colour changes and effects. Bi-colour plus gels is a different workflow that can make sense when most of your work requires high-quality tunable white and coloured output is only an occasional requirement.

Does a gel reduce light output?

Yes. Every gel absorbs part of the light passing through it. Light correction gels may cause modest transmission loss, while deeply saturated colour gels can absorb a substantial amount of output.

Does the CCT setting change how a coloured gel looks?

Yes. The gel filters the spectrum produced by the source, so the same gel can look different over a warm versus cool white-light setting. Evaluate the fixture and gel as a combined system rather than treating them as independent controls.

Do gels behave the same on LED and tungsten sources?

Not exactly. LED and tungsten have different spectral distributions, so the same gel may produce a somewhat different result on each source. For precise colour work, test the specific fixture and gel combination on camera.

When should I use a gel instead of changing the Kelvin setting?

Use the fixture’s CCT control when the desired correction is within its white-light range. Use a gel when you need green-magenta correction, a stylised colour, a practical-source match or a colour outside the fixture’s tunable-white range.

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