A Basic Introduction To Using Gels With Flash
Flash gels play several important roles in photography. Gels can convert the colour temperature of your flash, helping you balance your flash’s output with any ambient light sources. Gels can reduce light output without impacting colour for times when even a low-power flash setting may be a bit too much for your subject or environment.
Gels can diffuse light (i.e. make it softer) or add a dash of colourful for creative effects to your scene, like dousing colour across a subject’s face or changing the colour of a grey background to purple.
There are an overwhelming variety of gels from various manufacturers in different cuts (strengths) together with a wide array of colours, resulting in an abundance of ways to gell your flash.
You can see examples of colours and strengths on the Lee Filters
Website Link Here https://www.leefilters.com/lighting/colour-list.html#
If you are new to using gels and there uses, I think following information will is a good starting point.
Cut down on the amount of light emitted by your flash without changing colour temperature.
Great for: Subjects in dimly-lit areas when shooting with a wide-open aperture where even the lowest power flash setting might be too bright.
As the name suggests, diffusion gels take the concentrated burst of your flash and soften/spread it out. You can purchase diffusers based on light loss, measured in stops. Diffusers won’t typically be coloured, though some vendors sell diffusion gels that have slight colour casts to complement skin tones.
Great for: Anything (even faces) with shiny surfaces that may produce glare. A wide-angle diffusion gel is also useful to push light out to the corners of your frame if you need more coverage.
(PLUS GREEN, CTO, CTS, CTB)
Corrective gels are sold in varying strengths measured in fractions, with full strength typically indicated with a “full” in the product name. You can add gels together to boost their strength, so if your ½ gel isn’t cutting it, you can add a ¼ on top of it and the combined ¾ could do the trick.
Available in nearly every colour of the rainbow, these gels will transform your flash’s output into their colour. Most gel manufacturers make starter kits that bundle a selection of corrective gels and a few coloured gels; they’re an ideal place to start if you haven’t already stocked up. With coloured gels, there are no hard-and-fast rules. You’re free to experiment with their effects to your heart’s content. Or until your flash battery dies.
Great for: Creative effects and adding more drama to your image.
CTO (COLOR TEMPERATURE ORANGE)
Converts your flash’s daylight output to a warmer tungsten.
Great for: Balancing ambient tungsten lights. It can also be used creatively to create a warm vibe to your photo.
CTS (COLOR TEMPERATURE STRAW, OR OFTEN JUST “STRAW”)
Similar to a standard CTO gel but with a more yellowish hue.
Great for: A nice alternative to standard CTO gels if those are giving your subject too much of an orange tint. Straw gels are ideal for warming skin tones.
Balances your flash output to match fluorescent lighting, which gives off a green cast.
Great for: Shooting in spaces with fluorescent lights. Note: The colour temperature of fluorescents continues to change so they’ll no longer throw out a putrid green cast on your subject. Best to first take a few test shots without a plus green gel under fluorescent lighting.
CTB (COLOR TEMPERATURE BLUE)
Converts tungsten light to daylight, the opposite of a CTO gel.
Great for: Creating a cooler, bluer tone to your image and corrects for tungsten ambient sources.
There are numerous manufactures of gels but the Lee Website https://www.leefilters.com/lighting/colour-list.html# has downloadable apps for phones and the iPad, together with Gel Mood Boards and technical information.
If you do not wish to buy gel sheets or roles here are some gel systems and product links