Shot taken using both a pink and a purple gel, both under-exposed relative to the key light. Model: Sarah Arnold
We've all done it; grabbed a fresh pack of gels and opened them up to see those vibrant and saturated colours that match the brightly coloured swatches on the back of the packet. We throw them on our lights and take some shots, only to find that the actual colours appear nothing like we first thought. But why?
In this article I’ll take a look at a couple of reasons why our first attempts into gelled lighting can be a little frustrating and sadly, disappointing. Hopefully with some of the tips I outline here, you'll be well on your way to richly saturated coloured gel shots in no time.
Gel Exposure
First and foremost, the biggest reason for insipid looking colours when using gels, is exposure. I am of course referring to how bright or dark you have your gelled light in relation to the camera.
Correctly exposing coloured gels is arbitrary at best and the sooner you come to terms with that fact, the easier your gel work will be. There simply is no ‘correct’ exposure for gels.
Take a look at the two shots above. Imagine we have our camera and key-light on our model correctly exposed at f4. We then light meter our orange gelled backlight to f4 and take a shot. The colour, like we see above, is insipid and washed out, but how can that be? We've 'correctly’ exposed it to our camera setting, why is it looking so washed out? Unfortunately, gels can't be light metered like normal lights, so what we have to do is reduce the light on the gelled light or like in the image above shoot at a smaller aperture, to reduce the amount of light entering the lens. By simply reducing the gel light by two stops of power, we get an intense, rich colour instead of a washed out one.
To those wondering why you can’t simply light-meter a gel; it’s due to the fact that the meter only sees in grey. It can’t see the colour you’re trying to achieve so it’ll often trick you into over-exposing your colours as a result.
This image is made up of 13 different gels and it documents what they all look like at different exposures when shone onto a plain white wall. They are metered at the central point in the image to maintain consistency. The f numbers at the side represent the f-number the camera was set too, the power of the light stayed the same but I just let more or less light into the camera respectively. -Click to Enlarge-
The diagram above illustrates this point by showing you that the colour and tone of the gels changes drastically with exposure and although this might seem obvious enough, it's easy to fall into the trap of trying to 'correctly' expose something. All 13 of the gels used here were all shot with the gel relatively close to the wall as I wanted to include the hotspot and its falloff of light within the image. As a result you will probably witness many stops of exposure difference within any single frame but it helps to illustrate just how many different tones can be achieved with gel exposure alone.
If you’d like to learn even more about using gels on backgrounds and how to maintain a more uniform tone throughout the frame (no hot-spot or vignetting), then you will either need to move your gelled light further away from the wall or make the gelled light source larger. More information can be seen on this in this article Creating the Perfect Gelled Background
Model: Kimi Frances
As I mentioned earlier, I tend to always under-expose my gels and as you can see from the gel diagram above, the colours of the gels exposed at f11 or f16 are a lot more saturated and deeper in colour.
Remember these stops are just numbers, try to just think of it as two or three stops darker than your models key light or camera setting.
With the gels appearing darker like this, you tend to have a more consistent colour throughout your frame and they appear to have a more even exposure too.
Colour Contamination
Another major factor to bear in mind is how other lights in the shot will affect the exposure and the colour of your gels.
Trying to minimise the spill of light from other light sources onto your gelled colours will certainly help to maintain and hold their saturation. For example, if your models key-light is spilling onto your gelled background, no matter how much you under-expose your gels to maximise saturation, they will always look washed out.
There are a few ways to combat this. You could flag all of the lights that might be spilling onto your background or increase the inverse square law theory (essentially move your key light closer to the model thereby increasing the falloff rate of light to the background). This is a last resort though, as this will of course change the properties of light i.e hardness of light falling onto the model. Alternatively the easiest and usually the most overlooked solution is to move your model and all other lighting away from the gelled background. Try to treat it like you are lighting two completely separate sets; your model, and your background. No light from either set should affect one another.
When your background was a white wall, it obviously matters very little if your models key light is spilling onto the background. With gels however, this additional light falling onto the colour will 'contaminate' it and drastically change its appearance. Colour contamination is literally a whole other article in its own right, so if you'd like to learn more on the finer details of avoiding it you can see everything explained further here KEEPING Perfectly Lit Gelled Backgrounds
Gel Density
One other key point when exposing for gels, is to remember that not all gels were created equal. As you can see from the gel exposure diagram at the top of this article, even though they were all shot at the same time and with the same settings, some gels are blown out completely and some are very dark at the same exposure. This is because some highly saturated gels like reds and blues, need to be physically quite dense or thick, this in turn reduces the amount of light that passes through them which gives them the impression of being darker and more saturated. Conversely, some gels like yellows are very thin and let a lot of light through them. This may seem obvious, but the point I'm trying to make is that there isn't a strict rule of every time you use a gel you need to underexposure it by 2 stops. Some gels will need a lot more or less power than others and over time you'll get used to which ones require more light.
It may even be a good idea to do a similar test to the one I did, with your own gels and see what colours can be obtained. Using your specific gels will enable you to get a feel for what they look like over and under exposed (lighter and darker relative to the cameras exposure).
Of course, if you want to buy my gels that I use, you can find all the details about them here JHP Colour Gel Packs. More details below.
Key points to Remember:
There is no ‘correct’ exposure for your gels. Only lighter resulting colours and darker resulting colours relative to your cameras exposure setting.
Your gels will appear more saturated the darker they are in the image.
Darker gels appear to give a more even tone throughout the frame.
Moving your gelled light further away from your background will give you a more even exposure from edge to edge and a more even colour throughout.
Minimise the contamination (light spill) of other light sources on set. This is especially important on some of the thinner gels like yellow.
Not all gels were created equal, some of them are very thick and will need a lot more light to create certain looks. These are usually the very saturated colours like the reds and blues.
Of course, if you don't already own some gels and you're looking to get some, please feel free to take a look a the collections of gels I've put together. These collections are what I use day to day to create some of the most highly saturated colours around. If you're looking at getting into gelled lighting or need to get stronger and richer colours in your coloured gel work, why not check out my Jake Hicks Photography Gel Packs
If you guys have any questions about any of the topics I've mentioned or if you have anything to add, please do so in the comments below as I'd love to here your thoughts too :)
Thanks for reading :)
:WARNING: Yet more opportunities to spend money on cool stuff below :D
If you're interested in any of my work and would like to know more about how I created some of my shots then why not check out my workshops. Here you can find out everything there is to know about Gelled Lighting, Long Exposure Flash Photography and my entire Post-Pro Workflow. Jake Hicks Photography - Workshops
I have also just released a brand new 22 hour complete Gelled Lighting Tutorial video. I go over everything from studio lighting setups with gels to being on location with gels plus I also go through my complete retouching and post pro workflow. For more details and complete breakdown of everything that's include check out my Coloured Gel Portraits Tutorial
I also offer comprehensive coloured gel packs. These collections of gels are what I use day to day to create some of the most highly saturated colours around. If you're looking at getting into gelled lighting or need to get stronger and richer colours in your coloured gel work why not check out my Jake Hicks Photography Gel Packs
