LAST MONTH I kicked off this mini-series on composition by examining how to create a feeling of depth in our photos. This time we’re looking at another factor with the power to transform our images – colour.
The world around us is filled with examples of the visual power of colours, from flowers growing in the garden to carefully designed product packaging in the supermarket.
Colour theory is a complex subject, and while everyone’s tastes are slightly different there are certain guides that can greatly benefit our images. Colour matters, because we associate it with feelings and emotions.
Scientific studies have shown that colours can even affect us physiologically. Restful blue hues have been proven to slow heart rates and even bring down blood pressure. It helps us understand why simple underwater silhouettes are such pleasing pictures (dig out the March 2014 issue of DIVER for that specific column on those techniques).
Red is the opposite. It is the most stimulating colour and is associated with love, passion, even war and warnings (think of all those road signs). It too can have a physical effect, raising our blood circulation and breathing rates.
However, away from the Western world, red has different associations.
In China, red is a lucky colour attracting prosperity and happiness. It is even worn by brides. In the Middle East it is a colour associated with evil, while red is the colour of mourning in South Africa. It is also widely associated with communism. It is all a reminder not to get too caught up in detailed psychology.

RARELY WILL we use colours in isolation. As underwater photographers, we will typically blend colours in our compositions. And colour theory becomes even more valuable for our images when we consider how to combine them.
Perhaps the first rule to remember is that too many colours make a mess. As when everyone speaks at once, the message is lost. A couple of voices, ideally in harmony, work much better.
Complicated colour theory is too much to grapple with under water. Instead, I like to keep it simple, thinking of all colour combinations in one of two ways: either as opposite colours or similar colours. Both have a role to play in underwater images.
Practically in our wide-angle photography, our backgrounds will commonly be blue, green or something in between. These are classified as cool colours.
Similar colour schemes combine these blues and greens with matching, cool-coloured subject matter.
Meanwhile, opposite colour schemes combine classic water colours with contrasting warm-coloured subjects, such as yellow sponges, an orange frogfish or red soft coral.

THE EYE IS attracted to areas of contrast and it is something that we use knowingly or subconsciously whenever we compose underwater photos. Contrast is formed by light against dark, such as the dark silhouette of a manta ray against the brightness of the tropical sun.
Although dark versus light is the dominant form of contrast, it is not the only one. Contrast results from any opposing visual elements in our pictures. The message is that contrast is eye-catching – and we want it!
Colour contrast, using a foreground subject that has the opposite colour (that is, warm reds, yellows and oranges) to the background (blues and greens) is one of the best ways to inject underwater images with impact.
Think how eye-catching an orange garibaldi looks framed in front of giant kelp, or a yellow anemonefish and red-skirted anemone balled up in the late afternoon against the deep blue waters around a coral reef. They look great.
The key is to keep it simple. Colour theory is extensive, but making it confusingly over-complicated simply renders it useless under water.
When I first started attending BSoUP meetings, one of the most commonly repeated nuggets was simply “get a bit of red in the frame” – and that still holds true today.
Backgrounds are typically blue, so the take-home message for eye-catching, contrast-filled images is to focus our attention and cameras on warm-coloured foreground subjects.

CONVERSELY, A PALETTE of similar colours is restful for our eyes and creates a feeling of tranquillity, an emotion appropriate to many underwater scenes.
There are two ways to achieve this type of colour scheme. The first is to shoot monochrome scenes, typically wide-angle photos without flash and without manual white balance. This gives an image that is a pleasing range of blues and greens.
Setting the white balance manually in-camera, or afterwards using the handy eye-dropper in Lightroom, will correct the colour cast, but will often rob our images of this atmosphere. Just because we can do it doesn’t mean that we have to. This is why I regularly advise photographers shooting wreck internals or caverns to leave the image blue.
The second road to serenity is, when shooting with strobes, to select neutral (silvery fish) or naturally blue or greeny-blue subjects to combine with the blue background water. Kelp, seagrass, turtles and some fish all come in greeny hues and combine agreeably with the similar-coloured water.
Such shots rarely win contests, but their more calming qualities make them far more appropriate to hang on the wall. A simple, blue-green image of patterns of light playing on the seabed will be much nicer to live with every day than a gaudy red frogfish.

COLOUR IS ONE more thing to think about when we’re in the pressured underwater environment. Sometimes we will remember these ideas and use them under water, but on other occasions we won’t think of the theory but shoot the colour combinations we like simply because they “look nice”. This is colour theory working subconsciously.
The third way of using colour theory comes when we process our images, when we can tweak the colours of our shots to maximise our message.
Imagine a simple picture of a yellow sponge against blue water. If we want the maximum contrast we can tweak the colours in post-processing (using the HSL menu in Lightroom) for a cooler (bluer) blue and a warmer (orangey) yellow sponge.
If we want a more restful image, we may choose to process the sponge to a more greeny yellow, creating more similar hues to the background.
These small adjustments make a big difference in feel. With the modern tools at our disposal, colour theory has never been more relevant to the underwater photographer.
Colour theory is there to help us produce outstanding images. It is something that can add extra polish to our work, but in focusing on it, it is not a topic about which we should obsess.

With so much to think about under water, colour theory is often easiest to study and use when reviewing pictures. Don’t use it to choose your favourites. Instead, it might help you explain why you like certain shots.

Cool blues speak of the tranquillity of the deep, while warm colours push subjects forward, making them jump out of the frame.
To get colour theory to work we want rich, correctly exposed foregrounds and backgrounds.

While reds, oranges and yellows look great against both blue and green water, the latter gives less impact because of the extra warmth in the background colour.
Try combining green water with pink and purple subjects, such as starfish, jewel anemones and so on.