How Color Gels Can Improve PhotographyUpdated 10 months ago

How Color Gels Can Improve Photography

Color Gels can be extremely effective tools to help you create unique and dynamic photographs, and they've been around since the early days of film photography.

The two most common reasons why you would want to use color gels with your flash are for adjusting/balancing color temperature or adding color for a creative effect.

Balancing Color Temperature

Photography is the art of capturing light.  It literally means “drawing with light”, taken from the Greek words “photos”, which means light, and “graphé”, which means drawing. We all know that light can present itself in many different qualities such as color, hue, temperature, and density.

We can’t always control 100% of the light around us, but we can change the color of our flash to balance the ambient light - the surrounding environmental color temperature. 

The color temperature of almost all hot-shoe flashes is generally set at 5500° Kelvin, which is very similar to the color temperature of natural daylight.  Since we will often find ourselves using sunlight in our photographs, flash manufactures decided long ago to make our flash color temperature match the same color temperature we see in sunlight. So that's useful for photographing outdoors when we need to add flash to create a specific lighting pattern, but don’t want our flash to look any different than the light the sun is producing.

The Need for Gels

So why do we need gels? Gels are used when we want to balance the color temperature of our flash (5500°K) to be used in an environment where the predominant light source is not sunlight. Like when we're indoors. The above graphic illustrates a variety of common color temperatures and where they're found, shown on the Kelvin color temperature scale. 

Even though most interior lights are now closely calibrated to match the daylight color temperature, often times we will be photographing in reception halls, commercial buildings, or even in our own homes which may not share the same color temperature as our flash.

Most interior light sources are generally one of two types of light sources: incandescent light bulbs  (tungsten), or fluorescent tubes.  Both of these light sources have very different hues and color temperatures. Most incandescent light bulbs emit a color temperature of 2800°K, which is much warmer than our flash. Using a flash in a room with a predominant warm tone will make your subject or surroundings look very cool. This results in lighting that looks unnatural. In this situation, if you try and color correct the same photograph, you can color correct for the subject, but the surrounding color temperature will also get warmer, making the room look much warmer than it really was. Color balancing your flash is all about making the scene look as natural and as even as possible.

What Specific Gel Colors do

1/4 CTO, 1/2 CTO, or Full CTO (color temperature orange). This will “warm” up your flash color temperature to balance the color temperature of the sunset, or interior light bulbs. Each gel has a different intensity of warmth, and you will use either one, or a combination of two or more to suit your needs. The 1/4 CTO gel will convert daylight light sources (5500°K) to a warmer color temperature (4500°K), where a Full CTO gel will convert daylight light sources all the way to 2900°K, which is very close to incandescent light bulbs. 

1/2 Straw.  This is very similar to 1/2 CTO in that it is a warming gel, but 1/2 Straw has a tad bit more yellow hue in it which is best used for warming people and skin tones. Sometimes a 1/2 CTO can be too orange, making it harder to properly white balance in post production. The 1/2 Straw will make skin tones appear a bit more natural, without as much orange hue. 

1/2 Plusgreen. Another common situation where you need to balance your flash is when photographing under fluorescent light sources. These lights are warmer, in the 3800°K range, but also have a green tint to them. Using a bare flash on your subject (5500°K) will look good if you balance for daylight in post production, but the ambient light from the fluorescents will make everything else look green. This might be the effect you want, but you can eliminate the green surrounding areas by changing your flash to match the fluorescent lights by using a 1/2 Plusgreen gel.

Photographer: Eric McCallister
 

FULL, 1/2 CTB (color temperature blue, or cooling). These gels would be commonly used to “cool” tungsten light sources to make them more white, but since our flash is not a tungsten color temperature, but daylight balanced, this gel can be used more as a special effect. If you’re shooting during sunset, and you had a 1/2 CTB gel on your flash to light your subject, this will make your subject cool. But later in post-production, you can alter the white balance so that your subject is now daylight balanced, and the environment will be pushed warmer, making your sunsets even more dramatic.

8x Neutral Density (3 stops).  A neutral density gel is the same as what would be used for landscape photography when you want to reduce the amount of light reaching your sensor without any color bias. An 8x Neutral Density gel will reduce the light output of your flash by 3 stops. This is helpful when you want reduce the power output below the minimum output your flash is capable of, allowing you to decrease the effect of your flash when using large apertures. This would be necessary when attempting to shoot indoors in dark environments where the minimum power setting is still too bright, like at a wedding reception or other event photography situations.

Photographer: Trevor Crosby

 Our MagMod Pro Gels and MagBox Gels

The first set are the Corrections Gels:

• The Pro Correction Gels include 6 colors: Full CTO, 1/2 CTO, 1/4 CTO, 1/2 Plusgreen, 1/2 CTB, 8x ND
• The MagBox Correction Gels include 8 colors: Full CTO, 1/2 CTO, 1/4 CTO, Full Plusgreen, 1/2 Plusgreen, Full CTB, 1/2 CTB, 8x ND
• The Correction Dome Gels include 6 colors: Full CTO, 1/2 CTO, 1/4 CTO, 1/2 Plusgreen, 1/2 CTB, 8x ND

The second set are the Creative Gels:

• The Pro Creative Gels include 6 colors: Blue, Red, Orange, Yellow, Green, Purple
• The MagBox Creative Gels include 8 colors: Blue, Red, Orange, Yellow, Green, Purple, Magenta, Teal
• The Creative Dome Gels include 6 colors: Blue, Red, Orange, Yellow, Green, Purple

The third set are the Artistic Gels:

• The Pro Artistic Gels include 6 colors: Cyane, Amber, Aqua, Pink, Lavender, Lime
• The MagBox Artistic Gels include 8 colors: Cyane, Amber, Aqua, Pink, Lavender, Lime, Coral, Rose
• The Artistic Dome Gels include 6 colors: Cyane, Amber, Aqua, Light Pink, Lavender, Light Green

Below is a great video that shows examples of using MagBox Gels in action. It's a good education in how to use Gels to your advantage.