Photographing Aboriginal rock art

There are many different techniques for photographing Aboriginal rock art (especially engravings). Adding some of these to your photographic arsenal makes a big difference to how you capture the details of rock engravings, especially when they are weathered:

• Natural lighting – take advantage of early morning or late afternoon light
• Oblique flash – low-angled flash to highlight grooves
• Water – pouring water on the grooves (or visiting after rain)
• String or chain – physically highlighting the grooves
• Photo-montage – combining multiple photos
• Post-production – digitally highlighting the grooves.

Natural lighting

This is the most obvious way of getting good photos of Aboriginal sites – angled sunlight in the morning or later afternoon provides sharper relief of the grooves. (Watch out for shadows though – a site may get better lighting in the morning or afternoon. Some sites are surrounded by shrubs and trees, and making it impossible to get the right natural lighting.)

Although many of the other techniques allow you to take photos regardless of ambient lighting, you need to find the engravings before you can take photos… so if you’re looking for new sites, it’s best to go when you’ve got the best lighting conditions.

Pros	No cost and no need for any special equipment or added weight!
Cons	Limits the time you can get good photos to a few hours a day

Oblique flash

A low and angled off-camera flash simulates low angled sunlight, enabling you to get great photos at any time of the day. It makes an incredible difference in bringing out the details of carvings and highlighting the grooves.

There are a few ways you can achieve this – all require at least one off-camera (remote) flash. You can trigger the remote flash in a few ways:

• Cable – using a long cable to connect camera with a separate flash (not recommended)
• Pre-flash or optical slave – a flash unit on the camera sends a “preflash” which triggers the remote units. This can be very effective if you have a camera with a built-in flash. However, you need a “line of sight” between the on-camera flash and the remote flash. Also, if you buy a cheap generic flash it probably won’t work in bright daylight.
• Radio triggers -a radio trigger on the camera hotshoe send a wireless signal to one more remote flashes. Some manufacturers like Canon and Nikon have expensive proprietary systems. I have three Neewer NW570 + Trigger that are fairly inexpensve and so far have proved reliable.

Regardless of which system you go for, set the camera to ISO 100, choose manual mode and start with 1/200 shutter speed and F13 aperture. Depending on the distance of the flash to the engraving you may need to adjust these slightly. Trial and error is best – don’t try and use TTL metering. If you use a wireless trigger, you can quickly and easily set up multiple flashes.

The results are the most striking of all the techniques. You can barely make out that anything in the photo below left which I took; the photo on the right by Michael (Sydney Rock Art) clearly shows the grooves of a club.

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The photo below is another striking example of the results you can get with oblique flash lighting. (These photos were taken about 30 seconds apart, from the same spot, with an engraving that was in the shade.)

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A few more tips:

• Try and align the flash/es in the same direction as the sun
• For best results, tripod-mount the flash/es so they are about a foot off the ground with a low angle. Ideally use a tripod with a reverse mount, so the flash is upside down and angled down!
• You can continue shooting at night and get good results – although you may need to manually focus.
• If you are photographing cave art, mount the flash directly on the camera to remove shadows. It also means you can shoot at a low ISO, even if you are in dimly lit shelter.

Pros	Lets you take great photos at any time of the day
Cons	You need to carry at least one external flash + spare batteries Doesn’t work so well with large carvings

(A big thanks to Michael from Sydney Rock Art, whose encouragement led me to embrace this technique!)

Water

Pouring water over the rock to make the grooves stand out is a tried-and-tested approach. This technique works best when you’ve got the sun low in the sky. Photographing engravings after rain can be effective, but if it’s still grey and overcast they can still be difficult to spot.

Pros	Easy to cover a large expanse of rock (if there’s a water supply nearby)
Cons	Lots of additional weight if you are need to carry the water.

String or chain

Using string/twine or chain is another common technique to highlight the grooves. It’s useful for capturing the position of multiple motifs in more complex sites.

The other useful application is photographing larger engravings, to make the entire carving stand out from the rock and to give it some context.

From experience, lighter colours often work best – most of the time, I use white chain.

If using chain, take care in placing and removing the chain so as not to drag it over the grooves.

Tips:

• String has the advantage of being much lighter and longer than chain, and comes in high-contrast colours (eg. Spear & Jackson 50m No8 Pink Brickline or GRUNT 100m Fluorescent Builders Line).
• Chain is easier to keep in position, but weighs a lot more than string or twine. After some trial and error, I’ve found 2mm White Oblong Chain works best (it comes in 2.5m lengths, and 25m of this chain is about 2kg).
• Using oblique flash can help place the chain correctly, when an engraving is weathered and the grooves not obvious.

Pros	Makes it very easy to photograph larger or weathered engravings
Cons	Adds weight (especially chain) Can take some time to “string out” engravings

Photo montage

Planar mosaic imaging uses hundreds (or thousands) of overlapping photos taken from 1-1.5m above the rock surface. These are then stitched together into one high-resolution photo using software, enabling a very accurate representation of the engraving/s to be captured.

To get the best results from planar mosaic imaging:

• Keep the camera parallel to the ground and at the same distance. Ideally reverse-tripod-mount the camera (so it faces the ground), but hand-holding also works. Just make sure you keep the camera level at waist or chest height.
• Avoid getting your shadow (or the shadow from the tripod) in the photos
• Set the ISO has low as possible and shoot in manual so all photos are consistent.
• To stitch the photos, I use Microsoft Image Composite Editor (ICE).

For more information on planar mosaic imaging, Sydney Rock Art has pioneered this technique and has detailed instructions on their Web site.

Pros	One of the most effective ways to capture the details of an engraving or engraving site
Cons	Can be time-consuming (both at the site and in processing the images)

Post-production

As an alternative to using string or chain to highlight grooves, engravings can be digitally highlighted. This works well when the grooves are faint but still visible, and with higher-resolution photos where you can zoom into the detail. I generally choose a white or pink colour, and set the transparency of the line to 60-70%.

Pros	Effective way to highlight carvings, with the ability to choose nost appropriate colour, line density etc
Cons	If grooves are weathered, you may not be able to see them when you edit the photo

Combining photographic techniques

Some of the different techniques work well together – and some don’t mix well…

	Natural lighting	Oblique flash	Water	Chain or String	Photo Montage	Post Processing
Natural lighting		Y	Y	Y	Y	Y
Oblique flash	Y		N	N	Y (Hard)	Y
Water	Y	N		Y	Y	Y
Chain / String	Y	N	Y		Y	Y
Photo Montage	Y	Y (Hard)	Y	Y		Y
Post-processing	Y	Y	Y	Y	Y

Photo montage and chain/string

For larger motifs, highlighting the grooves with chain or string and using planar mosaic imaging can be an effective way of capturing the detail of an engraving, or an an engraving site with multiple motifs.

It also avoids the distortion of taking a wide-angle photo, providing a more accurate representation of the engraving.

Photo montage and post-processing

The risk in highlighting grooves with chain is that you get it wrong: it’s easy to miss some of the detail in an engraving. This is especially frustrating if you stitch hundreds of photos, only to realise the chain hasn’t been correctly placed. The advantage of digitally highlighting an image in post-production is that you’ve still got the original photo, as well as the enhanced version. It’s also ideal for adding the highlights as an overlay.

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Photo montage and flash

This is one of the hardest techniques. It requires patience and a high level of consistency in both the angle of the flash and camera angle (which must be kept level and at the same height for every photo). I use this sparingly. It’s useful for larger engravings where the grooves are very weathered or the carving very complex, making it difficult to highlight the grooves with string or chain.

Flash and post-processing

Photos taken using an oblique flash often require minimal editing, as this technique highlights the grooves so well. However, with more complex engravings or groups of carvings, digital highlighting makes it much easier to see the figures and understand the scene being depicted.

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Flash and natural light

Normally when you use an off-camera flash to photograph engravings, the intent is to minimise natural light so that the camera is only picking up the flash. There are times when you may want to use the flash to highlight an engraving, but also allow natural light to provide some site context. By opening the aperture, you’ll still get the right exposure for the flash, but you’ll let in more natural light so the photo will include some of the environment around the engraving.

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What doesn’t work?

It goes without saying that using chalk or adding sand to grooves may be effective – but should never be used as this accelerates the weathering of the engravings.

Pouring water onto the rock to highlight the grooves then using oblique flash is generally counter-productive. The water reflects and scatters the flash, and you won’t get good results. It’s a similar result if you highlight the grooves with chain and then try and then use a flash – you’ll get deep shadows from the chain and it will look very unnatural.