**Using Color Correction Gels in Flash Photography: CTO, CTB, and CTG**
Today, we’re diving into the colorful world of color correction gels for flash photography. Whether you’re a seasoned pro or just getting started, understanding how these gels work can take your photos to the next level. We’ll be focusing on three main types of gels: CTO (Color Temperature Orange), CTB (Color Temperature Blue), and CTG (Color Temperature Green). Let’s explore how these gels can help you match or contrast your flash with different lighting scenarios.
### What Are Color Correction Gels?
Color correction gels are thin sheets of colored plastic that you place over your flash to change the color temperature of the light. They help you match the flash’s color to the ambient light, creating a more natural and balanced look in your photos.
### CTO Gels
**What are CTO gels?**
CTO gels are orange-tinted gels that warm up your flash’s light. They come in different strengths (full CTO, 1/2 CTO, 1/4 CTO) to provide varying degrees of warmth.
**When to use CTO gels:**
Imagine you’re at a cozy indoor event with warm, yellowish lighting, like incandescent or tungsten lights, which have a color temperature of around 2800K to 3200K. Without a CTO gel, your flash’s light (usually around 5500K) will look stark and unnatural compared to the ambient light. By adding a CTO gel, you can match the flash to the existing light, making your subjects look more natural and preventing that harsh, artificial look.
**Effect on the light and exposure:**
CTO gels will make your flash’s light warmer, which can help create a more inviting and flattering tone. However, since the gel absorbs some light, you might need to increase your flash power slightly to maintain proper exposure. For example, if you’re using a full CTO gel, which converts 5500K flash to about 3200K, you might lose around 1/3 to 1/2 stop of light.
**Scenarios:**
– **Indoor Party:** If you’re photographing an indoor party with warm ambient lights, using a full CTO gel will blend the flash seamlessly with the room’s lighting.
– **Golden Hour Portraits:** During the golden hour, the natural light is warm. A 1/2 CTO gel can complement the warm tones of the setting sun, giving a beautiful, cohesive look to your portraits.
### CTB Gels
**What are CTB gels?**
CTB gels are blue-tinted gels that cool down your flash’s light. They also come in different strengths (full CTB, 1/2 CTB, 1/4 CTB) to adjust the degree of cooling.
**When to use CTB gels:**
Picture yourself shooting portraits outdoors on a bright, sunny day or in an environment lit by cool, blue daylight, which has a color temperature of around 5500K to 6500K. By using a CTB gel, you can make your flash light match the natural daylight, ensuring your subjects don’t end up looking too warm or yellowish.
**Effect on the light and exposure:**
CTB gels will give your flash a cooler, bluer tone, which can be great for mimicking natural light or balancing with fluorescent lights. As with CTO gels, you’ll lose a bit of light, so adjust your flash power accordingly. For example, a full CTB gel converts 3200K flash to about 5500K and may reduce the light output by about 1/3 to 1/2 stop.
**Scenarios:**
– **Outdoor Portraits:** On a sunny day, using a full CTB gel will match your flash to the daylight, preventing a mixed color temperature in your photos.
– **Indoor Fluorescent Lighting:** If you’re shooting in an office or a studio with daylight-balanced fluorescent lights, a 1/2 CTB gel can help match your flash to the cooler ambient light.
### CTG Gels
**What are CTG gels?**
CTG gels are green-tinted gels used to balance your flash with the greenish hue of certain fluorescent lights. They are less common but essential in specific scenarios.
**When to use CTG gels:**
Imagine you’re shooting in an office, school, or hospital where the lights have that characteristic greenish tint, often around 4000K to 4500K. Without a CTG gel, your flash’s light will look very different from the ambient light, creating an unnatural mix. Using a CTG gel helps blend your flash with the existing lighting for a cohesive look.
**Effect on the light and exposure:**
CTG gels will give your flash a greenish tint, matching it to the fluorescent lights. As with the other gels, be prepared to adjust your flash power to compensate for the slight loss of light. The light loss is usually minimal, around 1/3 stop or less.
**Scenarios:**
– **Office or School Shoot:** If you’re photographing in an environment lit by older fluorescent lights, using a CTG gel will prevent your flash from standing out with a different color temperature.
– **Mixed Lighting Situations:** In spaces with a mix of natural and fluorescent lighting, combining a CTB and a CTG gel can help balance the flash to both light sources.
### Matching vs. Contrasting
**Matching:**
When you want your flash to blend seamlessly with the ambient light, use a gel that matches the color temperature of the existing light. This creates a natural, cohesive look. For instance:
– Warm indoor light (incandescent/tungsten): Use a CTO gel.
– Cool daylight: Use a CTB gel.
– Green fluorescent: Use a CTG gel.
**Contrasting:**
Sometimes, you might want to contrast your flash with the ambient light for creative effects. For example:
– Using a CTO gel in a cool daylight environment can create a warm, spotlight effect on your subject.
– Using a CTB gel indoors with warm lighting can make your subject stand out with a cooler tone against the warm background.
### Final Tips
1. **Experiment and Adjust:**
Don’t be afraid to play around with different gels and power settings to get the look you want. Photography is all about experimentation!
2. **White Balance:**
Remember to set your camera’s white balance to match the lighting conditions you’re shooting in. This will help ensure accurate color reproduction in your photos.
3. **Practice Makes Perfect:**
The more you practice using gels, the more intuitive it will become. You’ll start to see the effects they have on your images and know exactly when and how to use them.