The Basics of Color Gels in Photography

The use of complementary and strong colors in photography is a growing trend. Modern advertising campaigns often use bold, contrasting colors to help draw attention to the message or product they want to promote. Color gels can be used to make your images pop. They are also known as filter gels or lighting gels.

Gels are a great way to make your images stand out from the rest and produce eye-catching results. In this article, we will look into how to use color gels to add a creative flair to your lighting, opening up a world of possibilities for your photo sessions. What are Color Gels?

Color gels can change the color of your lights by using pieces of semitransparent plastic.

There are two types of gels used in photography: creative color effects gels and color correction gels. These gels are used to create various colors that do not depend on the light source temperature. A red gel placed directly in front of light will turn it red. A yellow gel will make it yellow, and a blue one blue. Those are different from light temperature and tint adjustment gels, which are used to balance light sources with the ambient lights around you.

Temperature Correction Gels

Temperature adjustment gels will make a light source “cooler” or “warmer” depending on what is used. A CTO (color-temperature orange) can make the light warmter, while a CTB(color temperature blue), will make it cooler. The CTO and CTB gels can be easily confused with orange and blue gels so it is important to understand that those gels are not the same, and will not give a similar effect at all. One time, I tried to replicate sunlight with a yellow gel. It didn’t work.

A third gel that is rarely used, the plus/minus blue. This gel will give the light source a magenta or green tone. Essentially, there is a gel for each end of the “temperature adjustment” scale: CTO, CTB, minus green, plus green.

A selection of color gels.

A word of caution: Before we go any further, you must be aware that gels can melt when placed on a hot light source. You should avoid modeling lamps that are not LED-powered and heat resistant gels.

The Basic Rule of Color Gels

Let’s dive right into how to go about working with gels. Starting with the most basic rule of every gel: it reduces overall light output. Think of gels as obstacles that cut a portion of the light’s power. Some gels like Profoto and Expo Imaging might say how much light was cut by each gel. A blue gel can cut four stops of light while a yellow gel only half the light. It is possible to dial up the power and use gels with the strongest light available.

Let’s see how light falloff looks with a gel:

As you can see, the less light there is, the more saturated the color. Hence, when setting up a gel, the first thing you want to do is go low with the power and then dial it up to reach the look you are trying to achieve.

There will be a certain sweet spot between a dark saturated color cast and a burnt overexposed gel shot. However, neither one of these looks is correct. I create dark or overexposed images depending on the context. I like to use a very low-powered light with gels because, as you now know, less is more when it comes to working with color gels.

Let’s look at some practical examples where I used gels for effect and I will tell you exactly what I did and why.

Using Color Gels on a Fill Light

Because gels always show up in the shadow and need very little power to do so, I created a blue room in the studio just by gelling my fill light. Fill lights, as you all know, are meant to create shadows and make them invisible. You can fill your photograph with light by shining the flash in the ceiling.

While you may think that the blue is a traditional fill light, it actually is not. As the more careful ones will notice, there is a shadow cast on the background. My trick was to place a very distant light source and then gel it blue. The shadow helped add definition to the photograph. Nonetheless, because of a stark exposure difference between the gel and the key, I was able to get a clean white strip of light which then slowly graduated into the blue.

Using Color Gels for Background Gradients

Who doesn’t love a nice commercial-looking gradient? This image was created with a smooth gradient. However, there is a visible difference at the bottom and top.

To achieve this, I used a black background and placed a diffused umbrella with a blue gel at the bottom. The reason I wanted a large light source was because the background wasn’t perfectly smooth and all creases would show up.

Background Painting

This is where I feel like Jackson Pollock, what I mean by this is I get to simply play around with different lights in different positions. I love to create light patterns and shapes by having a lot of Cinefoil and flags and grids.

There really isn’t a clear-cut way to paint your backgrounds with gels. You can either create smooth transitions or have clearly defined lines.

For the picture below, I used three lights to light the background: a blue, pink, and yellow light. It had a tight grid so I could only see a small amount of light. The blue and yellow lights had barn doors so there was a bit of horizontal separation between the colors.

Background and Subject Painting

How many lights are in this picture? You are correct if you answer three. There is blue light, a lukewarm CTO, and a big fill light which is a full CTO. The two spots you see were created by using a very tight 5deg grid. The spots are irregularly shaped because the grid was not perfect. In this case, it makes the picture slightly imperfect but also much more interesting.

Using Color Gels as Lens Obstructions

Finally, an additional way to use gels without actually putting them on lights is by placing them directly on, or, in front of your lens. You will see some blurring and distortions that can be used to create unique images. With this method, you can capture some reflections off the glossy gel surface, some diffraction, and maybe even end up coloring some of the shadows.

Another interesting way to use light to illuminate the gel that you have wrapped around your lens is to place a lamp right underneath the camera. There is no exact science to this, so you just need to try and experiment with what you have to see what happens.

Closing Thoughts

Working with color gels is a lot about playing around and always feeling like a beginner, or at least feeling free. When I use gels I don’t think too much about what they do. I just put them on the light, and it does its thing. Then I go from there. The wonderful thing about this is you can be as creative as you want when adding colors to your lighting with gels.