Shoot a stunning subterranean scene!

Capture eerie and striking images of caves using light-painting techniques and long exposures

For this month’s Masterclass we’re leaving the sunlight behind, and heading deep underground to show you how to capture photos of caves illuminated using light-painting techniques. You’ll need a tripod and a couple of torches — a head torch will come in handy as well when you’re adjusting your camera settings. You’ll also need a remote release to open and close the shutter, as you’ll be using Bulb mode. Shooting in the dark can be tricky, so it’s a good idea bring someone along to help you.

When you’re composing your shot try to find an area of interest in the foreground, such as the entrance to a gallery or tunnel, that frames the image and leads through to an interesting area beyond — you’ll get the best results with a wide-angle lens, as this will exaggerate the perspective. If caves aren’t your thing, you can adapt these techniques for other darkened locations, such as old abandoned houses or a forest.

To capture the full brightness range of our scene we’ll shoot in Raw, then produce two versions of our image in ACR — one to bring out the detail in the torch-lit highlights and another to capture the detail in the shadows — and combine them in Elements.

Light up the darkness…

Set up your D-SLR to capture a long exposure, and paint your underground location with torchlight

Camera settings

1. Set your camera up on a tripod and select the Bulb mode. On some Canon cameras this is on the top Mode dial, labelled B; on others models you need to switch to Manual (M) mode, and adjust the shutter speed past 30 seconds — the next setting is Bulb. Set the aperture to f/11 to ensure your scene is sharp from front to back, and set the ISO to 100 to keep the image quality high and minimise noise.

Focusing in low light

2. Switch to Live View and set your lens to manual focusing (MF), then shine a torch on the main focal point in the scene (it’ll be easier if you have an assistant to do this for you). Navigate to the focal point on the rear LCD, zoom in to 10x magnification and adjust the focusing ring until the area on the screen is in sharp focus. As long as there’s nothing in the foreground of the frame that’s in front of the infinity point on your lens, everything will be sharp in the shot. Leave your lens se1 to MF to keep the focus locked.

Firing the shutter

3. To open and close the shutter you’ll need to use a remote shutter release, and as you’re shooting in Bulb mode you’ll need to time the exposure. Push the button on your remote forward to open the shutter, and pull it back to close the shutter again. Note that each make and model is different — some have a lock, so you don’t need to maintain pressure > on the button — so refer to the manual if you’re unsure about how to operate it.

Light painting

4. Use a torch or torches to paint light around the cave during the exposure. If you want to illuminate particular areas you’ll need to shine a torch evenly over the surface and move it in gentle sweeps; alternatively you can wave a torch around rapidly to create streaks of light. Look for interesting features such as stalagmites and stalactites to pick out, and leave areas dark where you want to create contrast and atmosphere. This part of the shoot is all about experimenting, so try different lighting effects to see what results you can get.

All about timing

5. Finding the optimum exposure time is very much a matter of trial and error. For our first attempt we opened the shutter for one minute, and from there we were able to gauge whether we needed to increase or decrease the exposure time. You don’t want to overexpose the highlights, so after you’ve taken the shot check the histogram in Playback mode (see the Super Tip over the page) and also check that your image is sharp by zooming in. We were eventually shooting with exposure times of around two minutes — if you have very powerful torches you’ll need a shorter exposure, and if you have dim ones then you’ll need a longer one. Most smartphones have a stopwatch function, which you can use to time your exposures.

White balance and torchlight

6. Different torches will produce light with different colour temperatures — one of our torches gave off a tungsten (orange) light, and the other was closer to daylight (blue). If you’re shooting Raw files, which we always recommend for maximum quality, you’ll be able to easily fine-tune the white balance post-shoot in Adobe Camera Raw or Canon DPP. If you’re shooting JPEGs then you’ll need to select the appropriate white balance setting — if your torches are producing a very orange light, for example, you’ll need to select the Tungsten setting.

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White Balance

Different types of light have different a colour temperature, which is measured in degrees Kelvin. Tungsten light, for example, has a colour temperature of around 3,000K, and produces light with an orange cast; selecting the Tungsten white balance setting on your Canon D-SLR will compensate for this by adding blue to neutralise the warm cast. If you have a mix of a light colours you may want to create a custom white balance setting, but as long as you shoot Raw files it’s easy to change the white balance post-shoot.

Super Tip!

Keep checking the histogram in Playback mode to make sure you’re not clipping highlights, which is easy to do if you shine your torch on one area for too long. Press the Info or Display button until the histogram appears. If the graph is cut off at the right-hand edge it means that highlights are clipped; if the clipping is relatively minor you’ll be able to recover detail in ACR or DPP, but if highlights are badly clipped you’ll need to adjust your exposure time and reshoot.

STEP BY STEP.Edit and enhance your cave shot

Crop in Raw

1. Go to File > Open and select masterclass_start. dng. We’re going to process this Raw file twice to bring out all the shadow and highlight detail, and then blend the two images together. Click and hold on the Crop tool, choose the 2 to 3 crop ratio, and crop the image to lose some of the uninteresting rock on the left-hand side and enhance the framing effect.

Lighten the shadows

2. Set Exposure +1.15 to lighten the image, then set the Shadows slider to +96 and Blacks to +90: this creates a fill light effect which brings out detail in the dark background areas. Set Contrast to +23, and Clarity to +24 to enhance the local contrast and bring out the textures in the rock. Click Open Image to open the image in Elements, and save it as a JPEG, naming the file masterclass_back.jpg.

Reopen the Raw file

3. Go to File > Open and select masterclass_start. dng again. Click the small menu icon at the top-right of the Basic panel to open the settings menu, and select Camera Raw Defaults to return all the sliders to 0. The crop that we applied in Step 1 will be reapplied by default, so we don’t need to crop image again.

Combine the images

4. In Elements select the Move tool, and drag the Masterclass_back image onto Masterclass_start, holding down the Shift key so the images are aligned. Next add a layer mask to the top layer, then press Ctrl+I to invert the mask from white to black to hide the upper layer and reveal the ‘Background’ layer below.

More Raw adjustments

5. This time we’re editing the image so that the lighter foreground is correctly exposed, so set Exposure to +0.55, Highlights to -60 to pull back the slightly overexposed highlights, and Shadows to +47 to lighten the dark areas in the foreground. Set Clarity to +38, and Saturation to +8 to boost the colours, then click Open Image.

Reveal the shadow detail

6. Select the Brush tool, and paint on the mask with a white brush at 100% opacity to reveal the shadow detail around the dark background area on the ‘Background’ layer, but don’t paint over the darkest parts as we want to keep them almost black to create contrast. Reduce the brush opacity to 50% to blend the shadow areas with the lighter foreground.

Boost the contrast

7. Add a Levels adjustment layer, and set the Shadows slider to 8, the Midtones slider to 1.16 and the Highlights slider to 231 to boost the contrast. Next add another Levels adjustment layer — we’re going to use this layer to add a tint to the image.

Add a tint

8. Select Green from the channel menu, and move the Midtones slider right to 0.85 to add a magenta tint to the image (magenta is the ‘opposite’ colour to green — if you move the slider left you’ll add a green tint). Click on the Levels layer’s mask, press Ctrl+I to invert it, and paint with a white brush at 50% opacity to reveal the magenta tint in the foreground areas.

Dodge and burn

9. Make sure the top layer in the stack is selected, and press Ctrl+Alt+Shift+E to create a merged layer containing all the visible layer content and effects. Next select the Burn tool, set Range to Midtones, Size to 500px and Exposure to 30%, and burn out the bits of boat and other distracting highlights in the shadow areas. Use the Dodge tool, with Range set to Highlights and Exposure to 10%, to lighten some of the highlights in the foreground, adjusting the brush size to suit.

Reduce Noise filter

10. There’s quite a bit of noise visible in the shadow areas that we’ve lightened, so press Ctrl+J to duplicate the top layer and go to Filter > Noise > Reduce Noise. Set the Strength slider to 10, the Preserve Details slider to 0% and the Reduce Colour Noise slider to 50%. Press OK to apply.

Selective noise reduction

11. Because our Reduce Noise settings soften detail, we only want to apply the effect to the shadows in the background. Add a mask to the top layer, press Ctrl+I to invert it to black to hide the effect, then take the Brush tool and paint over the noisy shadow areas with 60-pixel white brush at 60% opacity.

Tweak the contrast

12. To fine-tune the contrast add another Levels adjustment layer, and set the Shadows slider to 13 and the Midtones slider to 1.14. If you want to save your image as a JPEG to save space, go to Layer > Flatten Image; if you want to save the image with the layers intact, save it as a PSD file.

Super Tip!

There are a few tricks that you can use to help you compose an image in low-light conditions. You can take a shot using a flashgun or an LED light panel, or open the shutter in Bulb mode and fire a flashgun off-camera to illuminate different parts of your scene. The idea is to illuminate as much of the scene as possible initially, so that you can fine-tune the composition and decide which areas or details you want to illuminate in your final shot.

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Reduce Noise filter

The Reduce Noise filter’s Strength slider targets luminance noise, which appears as random light and dark pixels. The Reduce Color Noise slider enables you to target the random blotches of colour that appear in shadow areas, but don’t push this beyond the point where detail starts to be blurred. If details do become blurred, increase the Preserve Details setting to limit the noise reduction to areas of more even tone, where there’s less detail — you’ll usually have to settle on a compromise between removing noise and preserving important detail.

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