Photo Insight - Heather Angel explains how she constructed a water tank at home and used a darkfield illumination technique to capture this image of a cluster of trout alevins

Photo Insight with Heather Angel

Heather Angel explains how she constructed a water tank at home and used a darkfield illumination technique to capture this image of a cluster of trout alevins.

An internationally renowned photographer of

the natural world and author of more than 50 books,

Heather brings her expertise to AP.

These intriguing creatures may look a little like tadpoles, but they are in fact trout alevins. A trout alevin is a newly hatched trout before it grows into an adult freshwater trout. Trout go through several stages in their life cycle and this is the second stage. Once the trout egg has hatched it is called an alevin. The alevin bodies have yolk-like sacs that provide nourishment and a long tail that helps them to move. They are about 1in (2.5cm) long.

This shot required a fair amount of careful thought and planning. First, I had to track down a trout hatchery where I could find live trout alevins. The owners kindly allowed me to take a few samples back to my studio where I?d designed and built a special tank to photograph them (see diagram below). I returned the alevins to the hatchery afterwards.

If you take time to really look at the structure of a subject and notice how translucent or opaque it is, it will give you an idea of how best to light it. I?d seen trout alevins in a large tank at the hatchery and, looking at the creatures, I realised that if I could light them from underneath they would glow against a dark background. Trout alevins are translucent enough to allow light through their bodies to reveal the intricate patterns. You can clearly see the detail in their bodies, such as the blood vessels and yolk sacs, which produces a dramatic photographic image. The subject must be as flat as possible for optimum effect.

I used my Nikon F camera with a 105mm macro lens and was shooting straight down. The background is black velvet, and velvet is a brilliant backdrop because it isn?t shiny. I attached the camera to an overhead copy stand, which has a handle so you can move it up and down to frame and focus the shot.

The exposure was approximately 1/250sec at f/11 and the colours are how they were at the time ? the trout alevins really are this colourful.

Working in my studio with the windows blacked out, I used two small flashes as a single flash could have caused the lighting to be uneven (the subject would have been brightly lit on one side but not the other). The flashes were positioned at a 45° angle underneath the base of the tank, just out of shot. I made sure the flashes didn?t shine directly into the lens as this could have caused flare, and I used a lens hood as a precaution.

Although the alevins are not active like fully grown fish, they do move around. This made composing the shot a little tricky and some of the tails have been cut off by the edge of the frame. However, I don?t believe in prodding the creatures to push them into position.

You may have difficulty obtaining trout alevins as trout are a valuable fish, but you could try using this technique to photograph other creatures, such as dragonfly larvae, and see what effects you get.

I started my career as a scientist and, consequently, I try to do things as accurately as possible. For me, it is paramount that the image is accurate and true but I am also trying to create images that are exciting to look at ? I don?t want to create just a record shot. Not many people will have seen trout like this and my aim was to show the structure of the trout alevins in an exciting way. I hope I have achieved this.

TALKING TECHNIQUE

Darkfield illumination is a technique commonly used in microphotography where a subject is illuminated against a dark background. Essentially, the technique involves lighting a subject at an angle so it glows brightly and ?leaps out? from the background. I made a tank, measuring approximately 10x10cm, from specially cut glass, using a translucent aquarium sealant to join the pieces of glass together (the sealant is toxic so be careful if you try this). Instead of a tank with four equal-length sides, I made sure the bottom plane of glass was longer to create a flange so I could raise the tank from the ground. The tank was supported on both sides by blocks of wood and filled with water.

To see more images by Heather visit www.heatherangel.co.uk. For information on courses run by Heather and her son Giles, visit www.photographyandphotoshopcourses.co.uk

Heather Angel was talking to Gemma Padley