When you are mixing flash and ambient lighting with two different color temperatures often you will see a different white balance in the shadows then you see in the lit area. Skin may appear too orange or shadows too blue. If shooting indoors the shadows may look too green. Now that you know to look for these, these discrepancies in your LCD while your shooting should be an alarm bell to consider using a gel on your flash. Fighting Green Casts

Color correction - Wikipedia Color correction - Wikipedia

With a slightly yellower coloration than the CTO ambers, the CTS straws represent a useful alternative when varying conditions (film emulsions and video systems, light sources and set, wardrobe and makeup) call for a correction that is less red." In late afternoon sun, I would want a 1/4 CTO gel and maybe switch to a 1/2 CTO as it got later. These do a decent job of warming the strobe to better match the late day sun. Continuing our run-through of areas relating to the color temperature of lighting, today we’re going to look at gels. Lighting gels can add a variety of creative flair to your lighting, such as taking a daylight-balanced light and making the light look like the pink glow similar to that of an evening sky. Or quite simply, a gel can be used to correct the color temperature to that of another light source. From 3200k tungsten to 5600k daylight, for example. It is common for a gel manufacturer to publish the transmission coefficient or even the spectral transmittance curve in the swatch book and catalogs. A low transmittance gel will produce relatively little light on stage, but will cast a much more vivid color than a high transmission gel, because the colorfulness of a light source is directly related to narrowness of its spectral linewidth. Conversely, the flatter its curve becomes, the closer the gel is to a neutral density filter.Don't forget that you can also modify the colors by playing with the white balance too. For example, if you photograph a subject with a tungsten white balance and use one flash with an orange gel, and another without a gel. The white balance will make the orange gelled flash will appear neutral and the ungelled flash will appear blue.

Gel Filter Sheet 16x20 Orange Color Correction Lighting Gel Filter Sheet 16x20

The blue gel was directly used towards a white wall to project the light in a very diffused way all over the room.

Closing Thoughts

For regular folks who’ve followed my work for a while, you’ll already know that I’ve spoken about the optical snoot a lot already, but if you’re unaware of what this magic modifier does, you can see my full review on it here: Optical Snoot Review

Teach yourself flash: Color temperature gels | TechRadar

Let’s begin by identifying the color of your flash. Your flash is the same color as full daylight, so if you took a photograph at mid day, in full sun and set your white balance to daylight and added a flash into the image, you would end up with completely matching color. This is your starting point. Full sun is a slightly blue light source and so is your flash. They both sit on the scale at 5500 K. 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. This process is bound to bring out some interesting blurs and distortion to help create a unique final image. 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. The reason they are known as gels is because they were originally made from gelatin. Plastic is a lot more long lasting, cheaper, and easier to use, so you're unlikely to find any flash gels still made from actual gelatin today. In this article we'll look at how you can use flash gels for balancing flash with ambient light, creative use of gels for colored lighting effects, how they can be used for reducing the light power, and creating softer lighting. When shooting with flash in the shade or an overcast day, set your camera to the appropriate setting for the ambient lighting - in this case, dial your camera’s white balance to approximately 6800K to match the ambient light. CTB

The second test with Morgane helped me better understand how to use the color correction gels, specifically the CTO and CTB gels. The main color-correction gels are "color temperature blue" (CTB) and "color temperature orange" (CTO). A CTB gel converts tungsten light to "daylight" color. A CTO gel performs the reverse. [3] Note that different manufacturers' gels yield slightly different colors. As well, there is no precise definition of the color of daylight since it varies depending on the location (latitude, dust, pollution) and the time of day. When using flash it becomes important to choose your own white balance because the white balance of the flash may not match the white balance of the ambient scene. The white balance not only changes throughout the day as the sun goes from the horizon to the center of the sky, but you will also find different white balance on a cloudy day or in deep shadow or shadows. Kelvin Scale

Creating Gradients with Coloured Gels — Jake Hicks Photography Creating Gradients with Coloured Gels — Jake Hicks Photography

Diffusion gels are used to soften the light coming from a flash. They are usually sold as 'diffusion' or 'frost' gels. They spread the light out as it hits the gel, and should be positioned some distance in front of the flash, rather than right against the flash head. See below examples - the diffusion gel used (Lee 216) causes about 1½ stops of light loss, the flash power was not adjusted to compensate for these examples. One of the main uses of flash gels is when you are photographing under colored lighting (e.g. tungsten, fluorescent), but need to add in a bit of extra lighting with a flash. Flashes are color balanced to daylight, whereas fluorescent lighting has a green tint, and tungsten appears quite orange.Find sources: "Color gel"– news · newspapers · books · scholar · JSTOR ( July 2012) ( Learn how and when to remove this template message)