3

New Eyes for Old Headhunters

And before setting out from this harbour I caused all the men of the ship and launch to collect together with their arms in their hands, and having set two sentinels in good posts and the men in the form of a squadron, I took possession of all the land in the following form; having taken off my hat I said, Be my witnesses noble and faithful vassals of the King our lord that I, Don Diego de Prado, his Captain and Commander, do take possession of all this land discovered and to be discovered in the name of the most invincible and Catholic King Don Philip the Third our lord, King of the Spains and West and East Indies, and of his predecessors for ever and ever, amen.  And they all responded three times in a loud voice, with heads uncovered, Long live the King our lord, and I forthwith asked the notary of the ship for an attestation and a royal salvo was fired with the artillery and arquebuses, and in the evening there were illuminations and a Salve Regina was sung, giving thanks to our Lord and to his blessed Mother for the favours received and praying him to grant us a good voyage and every good success in that expedition to his honour and glory, amen.
Don Diego de Prado y Tovar (1607), Relación Sumaria

An old proverb tells us that the real voyage of discovery consists not in seeking new lands but in having new eyes.  But this would have been lost on the seventeenth century sailors who ‘discovered’ for the Spanish king the islands off the southern Papuan coast.  In March 1603 the Portuguese mariner Pedro Fernández de Quirós received his Royal Orders from King Philip III of Spain to embark on an expansive voyage to the South Seas in search of new lands.  It had been more than 80 years since Ferdinand Magellan and his men had set sail on their westward voyage around the globe, ‘discovering’ the Philippines for the Spanish Crown.  It had also been nearly 40 years since that Most Catholic of Kings, Philip II, had instructed Miguel López de Legazpi to found a permanent Spanish settlement in the Philippines.  Establishing a base in the islands had been of strategic significance as a provisioning station for the Spanish galleons on their long journeys across the Pacific, carrying silks from China, spices from the Moluccas and silver from Mexico.  With the Portuguese and the Dutch, and later the English and the French competing for naval booty and supremacy, the establishment of tactical sea ports was from the onset critical to successful seafaring and trans-oceanic trade, and geographic knowledge and sea charts were jealously guarded national treasures in their own right.  This was an era of buccaneering, encouraged by European powers as a means of denying enemy coffers valuable trade income; who controlled the seas controlled the fortunes of rich maritime trade.
When Quirós set forth from Peru on his voyage of discovery wonderful things were expected of him.  Having already occasioned to sail the Pacific, for months Quirós had petitioned the Spanish king to sponsor an expedition in search of the legendary Terra Australis Incognita, the Great Southern Continent of the Antipodes, a land much imagined since the ancient Greeks.  
In 1603 Quirós received his long-awaited sailing orders from the Spanish Crown, and soon after his Royal Orders from the Viceroy of Peru.  Equipped with the San Pedro y San Pablo, the master ship which he captained himself; the San Pedrico under the command of Captain Luis Vaez de Torres; and the Los Tres Reyes, a smaller launch under the captaincy of Pedro Bernal de Cermeño, the expedition set sail from Callao, Peru on 21st December 1605.  Second-in-command and sailing with Quirós on the master ship was Captain Don Diego de Prado y Tovar, Knight of Calatrava and member of ‘one of the noblest families of Madrid, and … one of the oldest and most distinguished of Spanish Orders of Chivalry, founded in 1158’.
The ships stayed in close contact through much of the voyage westward to Manila.  But unease stirred early.  It soon came to notice that Quirós had substituted a large cache of water for personal trade wine, and on board freshwater was running low.  When Quirós decided upon what seemed an irregular route and failed to approach sighted lands, the crew grew suspicious of his motives and of his fit as commander of the expedition.  Don Diego de Prado warned Quirós of imminent mutiny, but the warnings were ignored.  Prado later explained the situation to the King of Spain in his summary expedition report:
Captain Don Diego de Prado knowing for certain that the crew of the [San Pedro y San Pablo] … were going to mutiny informed the said Quiros by way of confession through the Father Commissary of the Franciscans, who told the said Don Diego that he also knew it and had informed him and would do so again, but the said Quiros took no notice of it; so the said Don Diego, seeing the little remedy that was to be expected, asked leave of the said Quiros to pass to the [San Pedrico] … with his rations, which were the same as those of the said Quiros; he granted it to get rid of the bother ....  The said Don Diego knew who were the mutineers and how they wanted him for head, but he did not want to mix in such conflicts and lose the honour which he had gained in the service of his Majesty, so he at once shifted his things to the [San Pedrico] …, wherein the Captain thereof was very pleased.
 By the time the armada reached the large Melanesian island of Austrialia del Espiritu Santo – which Quirós claimed as the long-sought Great Southern Continent – ‘the mutineers effected their evil plan’.  Torres reported the incidence in his letter to the king:
the [San Pedro y San Pablo] … set out from us at one hour past midnight, without telling us of it and without making signals that we might understand it by them; this took place on the eleventh of June [1606], and although at once on the following morning I went out to seek it making the proper efforts, it was impossible to find them; for they did not go on the route nor with good wills:  so I had to return to the Bay [at Espiritu Santo] to see if perchance they had returned to it:  all this I did for further loyalty in this Bay.
In the darkness of night the sailors had taken control of the ship, confined Quirós to his cabin, and sailed back east to Acapulco, all the while putting Quirós’s precious wine to good use; we know of this from later communications in Manila between Prado and returned mutineers.  Barely halfway across their journey of discovery the expeditioners had lost their master ship, a significant part of the crew, and their commander.  
Captain Torres was now the highest-ranking officer.  ‘I waited for fifteen days for them’, he wrote to the King, ‘at the end of which I brought forth Your Majesty’s orders and calling a council jointly with the officers of the Launch, it was agreed that we should fulfil them, though against the inclination of many’.  Prado’s Relación Sumaria, for 300 years lost and unexpectedly rediscovered in the 1920s, records the ensuing events:
On the 25th [June 1606], S. John’s Day, Luis Baes again summoned a council and produced a closed and sealed paper, and said it was from the Viceroy of Peru; in substance it contained and said that in case any of the ships should go astray they should make every effort to go up to 20° of S. [latitude] … and see if there was any land in that region, and not finding it should go to the city of Manila and wait there for four months for the other ships, as they also carried the same orders; and in case Pedro Fernandez de Quiros should fail they were to take Captain Don Diego de Prado for chief in order that he might direct that voyage … The said Don Diego accepted the charge as committed to him, and thenceforth executed his office.
With Prado commander-in-chief the expedition resumed, eventually to venture south through the unfamiliar waters of the Straits that now bear Torres’s name.  It is here, winding through shallow waters within eyesight of both New Guinea and the Australian mainland, that Don Diego de Prado, the King’s Captain and Commander, took possession ‘of all this land discovered and to be discovered in the name of the most invincible and Catholic King Don Philip the Third our lord, King of the Spains and West and East Indies’.
When Prado and Torres successfully sailed the narrow straits between New Guinea and Australia in October 1606, they ended decades of speculation about a possible safe passage for west-bound seamen on the Manila trade.  But they were not the first across the Straits.  Nor were they the first to claim the islands as their own.  For millennia the islands, the reefs and the seas had been owned, occupied and travelled by Islanders, Papuans, and northern Aboriginal peoples alike.  A contested seascape, the Spanish mariners were but the latest in a long sequence of oceanic travellers.
The legend of Kabadul Kula
A seascape of immense beauty, Torres Strait has from this first European approach come to us as a bridge and barrier of human interaction.  To some the open waters allowed travel across vast distances; to others they served as impassable barrier between landmasses.  Yet while we have the early Spanish records to consult about early European visions of access and territory across the Pacific, insights into Indigenous history within the Straits are more problematic.  One answer is through the prehistoric inscriptions on the rocks, marks of territory and of cultural influence, and a window into the Islander past.
The cave paintings of Torres Strait are poorly known, partly because years after its creation rock-art can be hard to see, particularly in exposed tropical island settings. As archaeologists the world over have long asked, the challenge is how again to see the long-faded paintings of the deeper past.  This is the question we wish to answer, in the process accessing Torres Strait’s long history of foreign intrusions.
Torres Strait is most famous anthropologically as the place where the Melanesian and Australian Aboriginal domains meet and as a transition zone between the horticultural and hunter-gatherer worlds.  At the very northern end of the Straits is the island of Dauan, today as in the past an island in-between.  At Australia’s northeastern tip and within sight of the Papuan coastline – a vast expanse of coastal swamps – Dauan is home to Torres Strait Islanders, specialised sea peoples who are politically within Australian territory but culturally uneasily matched with either Aboriginal peoples to the south or Papuans to the north.
Dauan Islanders have long been a cog in international exchange, willing partners in a wide network of trade ultimately spanning all of the occupied islands of the Straits, much of the southern Papuan coast and the tip of Cape York.  But in a curious twist, until the end of the 19th century amicable relations would momentarily suspend as the Tugeri from the west, or the Kiwai from the east, raided Dauan for human heads.  Headhunting has of course now stopped, and friendly trade relations continue today under the Torres Strait Treaty.
In this fluctuating world of amity and enmity emerged the legend of Kabadul Kula.  In 1965, after been regretfully told by Islanders that their legends were being lost with the passing of the elders, amateur anthropologist Margaret Lawrie vowed to record and publish the traditional stories of the Straits.  Over the next three years one hundred and sixty-five legends were taped and transcribed from thirteen inhabited islands.  One of these was the story of Kabadul Kula, transmitted as oral history and inscribed onto the Dauan rocks by the Kiwai raiders themselves.  The Kabadul Kula story was recounted by Simona Naiama on 14th October 1968, to this day the only Indigenous recording of the story:
Abai, a woman who lived in the village of Buli on the island of Dauan, received a baby pig from friends on the northern mainland, together with the message that she should look after it for them until it grew up. This she did, and the pig grew big and fat, so fat that it could not walk. She then told the people of Buli to kill it, and when that had been done, the pig was eaten.
Now the pig had never belonged to Abai – she had merely been looking after it for the owners, her friends. Therefore, when they heard that their pig had been killed and eaten at Dauan, they were exceedingly angry and sent a message to Kiwai saying that they wanted the people of Dauan to be punished for their offence. The Kupamal, more than willing to fight at Dauan, immediately got together their fighting gear – clubs, bows and arrows, and bamboo beheading-knives – and loaded their canoes for the journey.
They set out late in the afternoon and reached Augur Gizu at sunset. It was naigai time, the season of the north-east wind, and they had been helped on their way by a steady breeze. After dark, they sailed on. Naigai was still blowing, and it stayed with them the rest of the way to Dauan, where they arrived late that night. They landed at Sigain Kup, a small cove, armed themselves, and climbed up the rocks at the back of the beach to an enormous boulder which they tried to roll down into the sea. They believed that if they could do so they would have proof at the outset that their combined strength was sufficient to overcome the people of Dauan. They could not budge it.
They went to the boulder-strewn area further back from the shore and, as it was not time to commence the attack on Buli, drew pictures with parma (ochre of red clay) on the underside of a huge rock while they waited.
The Kupamal set out for the village while it was still dark, advancing through the scrub in two columns. The two leaders ordered some of the men to remain hidden in the bushes; the rest they sent into the village where they were to disperse. Men were to steal into every house, and each man was to lie down beside a sleeping occupant.
Just before daybreak, a Dauan woman got up and went to the bushes, to the spot where the Kupamau leaders were hiding. They shot arrows at her. “People of Dauan,” she yelled, “there are enemies here! Either Gumulgal [Mabuiag Islanders] or Kupamal – I don’t know which.” Waked by her cries, the people of Dauan tried to dash from their houses, but every Kupam was ready to seize and club the victim he had marked, and few escaped. The Kupamal cut off the heads of the dead.
One man got away – a man named Kang – had been able to snatch up his bow and arrows, and he limped off, pretending to be a cripple. The Kupamal saw him when he reached a rock, near the monument which commemorates the “Coming of the Light” to Torres Straits, and urged one of their number, Kamumu, to go and kill him. “Kamum’! Mm! Mm!” they pointed. Kamumu did a frenzied dance and brandished his gabagaba at Kang. Kang shot an arrow into Kamumu’s heart.
Kang walked on a little further – to the site of the present-day Church. Another Kupam had gone out to kill him. Kang shot him through the heart also. He killed a third Kupam at very close range at Markai Katam [present village well]. The arrow used by Kang for his shot was bisikuik, one which had a man’s head carved on the head and a poisoned tip – with this arrow a man never missed. But it was the last of Kang’s arrows, so after he had fired it, he began to run away up the steep hill behind Markai Katam. Halfway to the top, he turned around and yelled down at his enemies: “Kupamal, come and get me!” But none of the Kapamal took up the challenge, all giving up the chase and going back to rejoin their comrades.
A Kupam who had had no part in the pursuit of Kang presently heard voices in the bushes behind the well at the back of the village and stole towards them. He saw a woman – Abai – and her children.
Abai, hearing no sound of fighting for some time, and believing, therefore, that the battle had ended, had gone to the spot at which she had prepared bui the day before and was feeding her children. The Kupam killed the small children and struck Abai a glancing blow with his gorapatutu, a small club. She dropped to the ground, unconscious. Her eldest son – a big boy – ran away and sat on top of the big rock called Kangan Gul (Kang’s canoe). He looked down on his mother and the dead children, and then he ran without stopping to the top of the hill.
The Kupam stood astride the body of Abai, sharpening his upi (Bamboo be-heading knife) with his teeth, his eyes sometimes on the woman, sometimes glancing around him. Consciousness returned to Abai. She looked up, saw the Kupam, and shut her eyes fast. She was lying on her back with arms outstretched. Now, always watching the Kupam through half-closed lids, she gradually moved her arms in to the middle of her body. The Kupam took his eyes off her – Abai brought her hands up, grabbed his genitals and wrenched savagely. He died of it.
Those men of Dauan who had escaped hid on either side of the path through the scrub between Buli and Sigian Kup and stoned and killed many of the Kupamal as they were returning to their canoes with the strung heads of their victims.
Some Kupamal reached their canoes. They sailed away with a south-west wind and came to Gawal Maza off Saibai – where the beacon is.
Two men, Iamaru and Kaigas, who lived at the western end of Saibai Village, saw the Kapamau canoes and said: “Where have they come from? Let’s go and find out.” They put a canoe into the water and questioned the Kupamal. On being told that the Kupamal were on the way home from Dauan, Iamaru and Kaigas went to one of the canoes and looked under a mat. They recognized the heads. While Iamaru and Kaigas were killing the men in the canoe, the other canoes sailed away.
These were seen at Mawat by Gamia, who went with other men to find out where they had come from. When Gamia and the men of Mawat saw the Dauan heads, they went from canoe to canoe and killed every one of the Kupamal except those in a single canoe which managed to escape.
Thus, of all the canoes which sailed from Kiwai for the punitive raid on Dauan only one returned.
The rock-art of Dauan
Dauan is a small island.  At less than three kilometres square it is one of the smallest permanently occupied islands in the Straits.  It is also the most rugged, a mountain-island of granite boulders fringed by narrow grassy flats and mangrove swamps.  The two hundred or so Islanders live in a small village on the island’s northeast coast; along the northwest coast are fertile soils that once supported extensive gardens, now long-abandoned.  For eight hundred metres the village curves round the island, a single coconut-tree fringed road straddling the beach.  In the past the people of Dauan obtained food principally from gardening – yams, sweet potatoes, taro, cassava, sugarcane, bananas and coconuts – and from fishing and hunting turtle and dugong.  Trade with neighbouring islands and the Papuan coast allowed widespread interchange of foods, items of material culture, and ideas, but the character of such exchange has changed with Western modernisation.  While hunting and fishing continue, gardening has dropped off in recent decades and most produce is now obtained from the local store. 
Too small and craggy to harbour an airstrip, entry into Dauan is from the sea.  Here, on the island’s Papuan end, are found the northernmost rocks of Australia, and amongst these Australia’s northernmost rock-art.  Lured by Kabadul Kula’s rock paintings we land on the neighbouring mud island of Saibai, the aerial port of entry into Dauan.  With us is Professor John Brayer, computer scientist and digital photography expert from the University of New Mexico, armed with a large case of electronic gadgetry.  Using the latest in digital technology, we head for Kabadul Kula, the last bastion of headhunting rock-art in Torres Strait and material evidence of past intrusions. 
Kabadul Kula is located on the northeast coast of Dauan less than fifty metres from the shore on the edge of the village. The art spans a wide arc under the overhang of a large granite boulder nearly six metres high.  Under a shallow rock overhang, many of the paintings are well protected from the rain and the wind, but some are exposed.
The colours of the paintings are faded. Paintings such as those at Kabadul Kula generally start out having good contrast, but over time, by a variety of processes such as photochemical change, the accumulation of dust, salts and mineral crusts, or the loss of paint through falling particles or rubbing animals, the images undergo fading, which tends to reduce the contrast between paintings and the background rock.  Sometimes, the colour differences do not totally disappear in an image, but just become not quite distinguishable to the human eye.  This, we hope, is what has happened at Kabadul Kula.
It is hard to tell from first sight why the Kabadul Kula paintings are so faded.  It is also hard to tell which of the paintings were made by the Kiwai raiders of the headhunting story retold by Simona Naiama in 1968.  But it is clear from this first visit that not all were likely to have been then painted, for some images are characteristically of Islander, not of Papuan themes, and the very different degrees of fading between groups of paintings imply more than a single artistic event.  The clearest, and the first painting as one approaches the rock, is a rather devilish figure reminiscent of the demonic characters of Western medieval tradition (Figure 1).  Yet here they are dogai, hideous spirit-beings with characteristically large ears in which to wrap themselves.  Dogai ‘lived in stones, or trees, or underground [sometimes in caves]. They could impersonate living women. Most dogai were evil and all were greatly feared’, writes Margaret Lawrie. They are a feature of the western and central islands of Torres Strait. Dogai are mischievous and even murderous and numerous stories tell of men trying to harm or kill them for wrong-doings. A white dogai on Gebar Island forty kilometres south of Dauan is ‘tall and skinny, with a face like a flying-fox. She had long teeth and big ears; indeed, her ears were so big that when she lay down to sleep, she could use one as a mat and the other as a cover to keep her warm’. On Dauan, dogai ‘were said to speak a confused gabble of the Island tongue’. Kabadul Kula contains the only known rock painting of a dogai in the world.
To the right of the dogai are other clear paintings of tasselled dancers and large geometric designs reminiscent of Papuan clan symbols.  And there are hints of older paintings underneath, faint traces of red pigment long effaced by the elements.  The slow disappearance of pigment worries archaeologists, for with fading elopes the past, but it is precisely this that at Kabadul Kula excites John.
John Brayer is a tall, quiet man.  He began his career in the 1960s with the photographic company, Kodak, developing tools for the computer-aided design of consumer and commercial photographic systems.  During the Cold War, he worked on the development of photographic spy satellite systems and later continued working on Landsat and Earth Resources satellite systems for land use classification.  For four decades John has been an active participant and an eyewitness to the development of image processing software techniques, and to the development of the digital camera into the inexpensive and convenient tool it has become today.  
During the 1980s John worked on medical applications of image processing and pattern recognition and also applied these methods to the analysis of very early printed documents (Gutenberg) and to the detection of forgeries and new states in etchings (Rembrandt).  He first became interested in materials from cultures without writing in the mid 1980s while working on computer-aided classification of the shapes of Native American Pueblo ceramics.  His first exposure to rock-art was at the Petroglyph National Monument in New Mexico, USA in 1976, but it was not until fifteen years later that he worked on a project at the same site helping young Pueblo students to record some of their own heritage.  After a couple of other small recording projects in New Mexico, we were introduced by a mutual friend and invited him to apply his computer skills to the recording and enhancement of rock-art in various projects, firstly in northern Australia, then in Vanuatu, and now at Kabadul Kula.
It is this knowledge and digital gadgetry and software gimmickry that John has brought with him to attempt recovery of what seems to us ancient and irretrievably lost paintings on the Dauan rocks.  Efforts to improve photographs – especially aerial photographs – had begun in the early years of photography, but received a big stimulus during and following the second World War.  Examples of early techniques included varying exposure times, using high contrast emulsions, selective masking of parts of an image and ‘unsharp masking’, a darkroom technique for sharpening an image by masking with a blurred negative of the original image.
In early 1950s France, Pierre-Michel Duffieux, Andre Marechal and Paul Croce worked-out the relationship of the Fourier Integral (used widely in communication theory) to Optical Image Formation by a lens, and thus invented Fourier Optics, which shows how to filter and improve images by optical means using lenses.  Optical processing got a big boost with the construction of the laser in 1960, but was never able the match the flexibility of processing and low signal-to-noise ratio of digital processing.
Continuous development of optical, analog and digital methodologies throughout this period was stimulated by the necessities of spy photo enhancement, but these technologies were not made public until the late 1980s.  A major stimulus was the ‘U-2 Incident’ in 1960 when the USSR shot down a US spy plane, necessitating a switch to satellite spy systems.  A major breakthrough for digital processing then came in 1965 with the development of the complex Cooley-Tukey algorithm for computing the Fourier Transform (FFT).
The general public first became aware of the uses of image enhancement and the field received further stimulus from the Ranger program of lunar spacecraft, 1961-1965. Ranger 7 sent back over four thousand three hundred television images of the moon which were enhanced to produce ten times better resolution than ever before seen.  But Ranger 7 impacted the moon in 1964; as a result of this and other space programs, Jet Propulsion Laboratories (JPL) of Pasadena, California, established its Image Processing Laboratory to process spacecraft images.
The 1970s saw rapid developments of computer hardware such as processors, memory, displays, scanners and printers.  But costs were very high.  Maturing of theory and publication of image processing books in the late 1970s led to wider availability of the techniques, and the training of a new generation of researchers.  Yet application of image processing techniques was still largely restricted to experts using expensive, specialized hardware and software.
One of the major reasons for the ten-year delay in wider use of image enhancement techniques was that computer user interfaces were not well developed or understood.  ‘Windows’ did not become widely used until Windows 3.0 in 1990 and Windows 3.1 in 1992.  Thus while image processing software was widely available to experts in computing in the 1980s, it was not easy to use.  This situation changed with the introduction of Adobe Photoshop 1.0 in 1990 and Adobe Photoshop 2.5, the first Windows version, in 1992.  Finally, image processing software was available cheaply and easily to the general public.
But digital cameras were still very expensive.  The CCD or Charge-Coupled Device, the basic image sensor chip in a digital camera was invented in 1970 at Bell Laboratories by Willard Boyle and George Smith.  It was intended primarily as a storage and delay device for use in audio and video signal processing, but one of its weaknesses for that application, sensitivity to electromagnetic noise, turned out to be its strongest asset as an image sensor.  Development continued with a 100x100 array produced by Fairchild in 1974, the first commercial television CCD cameras in 1975, a 500x500 array in 1978 and second generation devices of size 1024x1024 by 1982.
Early spy and space applications used conventional photography and then conventional analog television video systems.  Prior to the 1990s commercial digital cameras were analog video television systems with computer interface boards doing the analog-to-digital conversion.  In 1992 Kodak introduced the DCS200 camera based on a Nikon 8008 body that is the first commercially marketed self-contained digital camera.  In 1994 again Kodak introduced the DC40, the first consumer full-featured digital camera.  Also in 1994, the very popular Apple QuickTake appeared, which was very easy to use and was less than US$1000, but it was also of very low quality.  In 1995, the Kodak DCS 460, a 35mm SLR camera with 36-bit color and 6 million pixels appeared.  In 1996 the first digital camera using a compact flash card appeared.  And in 1998 the Nikon Coolpix 900 with over a million pixels for under US$1000 came on the market.  It is with the Nikon Coolpix that John had arrived on Dauan, ensuring the capacity for high quality photography necessary for digital enhancement.
Gathering round Professor Brayer like schoolboys, we try hard to follow his explanations behind the principles of digital enhancement, why it works.  ‘If we want to make the faded paintings on the rock clear again’, he gathers a small audience on Kabadul Kula’s rocky platform, ‘we first must understand something about light.  We must capture its energy and reshape that energy so it serves us.  We must now think of the art in front of us not as shades of paint but as light reflected off a rock surface.  The ancient theory of light, dating back at least to Aristotle, was that light was made up of actual physical corpuscles or atoms of light in motion, sort of like balls on a billiard table.  White light was believed to be a “pure” form and other colours were mechanically modified forms, maybe balls with dents in them, or balls spinning, or faster or slower balls.  Isaac Newton demonstrated the errors in these theories and the composite nature of white light in his famous prism experiments of 1665-6 in which white light passed through the prism was split or spread into a spectrum or rainbow of colours.  But Newton still believed light was corpuscular and mechanical in nature’.
‘Over the last half of the nineteenth century, James Clerk Maxwell, using the prior works of Ampere, Coulomb, Faraday, Gauss and Poisson, combined the principles of electricity and magnetism into a set of four equations, called Maxwell’s equations.  By analysing these equations, he was able to conclude that light was an electromagnetic wave phenomenon, that artificial electromagnetic waves might be generated in the laboratory (the basis of radio), and even predict the speed of light in a vacuum’.
‘So we have come to realise that light travels through space as electromagnetic waves of varying lengths.  The entire spectrum of wavelengths is called the electromagnetic spectrum, but only a small part of this spectrum is capable of producing visual sensation.  Other parts of the spectrum include radio waves, x-rays and infrared waves that have wavelengths longer than visible red light, and ultraviolet light that has wavelengths shorter than visible violet light.  Visible light therefore relates to a narrow range of the family of electromagnetic wavelengths.  This light consists of a “rainbow” or spectrum of electromagnetic waves of different wavelengths.  Colours of an object – such as a rock background or a painting – differ when the light that reflects off the surface has different amounts of light intensity in different parts of the electromagnetic spectrum (part of the incident light energy is absorbed by the object, depending on its surface properties).  A red surface has more intensity in the red wavelengths. A blue surface has more intensity in the blue wavelengths’.
‘We can give many of these colours a name, such as red, yellow, green, cyan, blue, magenta.  But really each of these names refers to how the spectrum of a particular set of electromagnetic waves is perceived by a person.  It is through the retina in the eye that our brain distinguishes different colours.  The human retina contains millions of light-sensitive cells that can be divided into two major types, rods and cones.  Through variations in chemical composition, three types of cones enable us to discriminate different colours.  A camera records the amount of light reflected from each point of a surface using three different sensors, each sensitive to a respective colour, called red, green and blue (R, G and B).  Likewise, a digital camera records the light reflected from a rock surface on a sensor consisting of a rectangular array of pixels, or picture elements.  Each pixel represents a tiny square area of the image, that is, the light reflected from a region on the surface of the rock.  For a colour camera, each pixel is really three different sensors, each sensitive to a respective colour corresponding to red, green and blue.  Three sensors are considered adequate because they are roughly equivalent to the way the human eye perceives colour using its three different types of cone receptors in the retina.  So three numbers, the R, G and B intensities determine the colour at a point or pixel in the image’.
‘Each pixel colour, represented by the three R, G and B numbers or coordinates, can be considered a point in a three-dimensional “colour space”.  Virtually any colour can be generated from a combination of red, green and blue.  In addition to the individual colours themselves, there are shades of grey from black to white, which are made-up of a combination of colours.  The less grey is contained within a colour, the more that colour is said to be “saturated”.  So “pure” colours appear deep and are called saturated’.  
 ‘In a typical rock-art image of a coloured foreground painting on a greyish or brownish background rock wall, a sample of pixel colours from the background region will be similarly coloured.  So the pixels’ R, G and B values are similar to one another and are close to the colour grey or brown which is the average rock colour. A group of pixels selected from the foreground figure region of the image will also be coloured similarly to one another, and there will be an average colour for the painting.  However, these colour points should be somewhat different from those of the background pixels. If the pixel colours of different image regions are a lot different, we say the image has good contrast. If the average pixel colours of different image regions are close, we say the image has poor contrast’.
‘Rock-art images generally start out having good contrast, but over time, by a variety of processes, the images undergo fading, which tends to reduce the contrast between foreground paintings and the background rock.  The process of fading tends to move the colour R, G, B values closer to one another and closer to grey so that differences – contrast – may eventually disappear.  If colours are close to one another – if the contrast is poor – the differences may not be noticeable to a human observer.  Colour scientists define the term “Just Noticeable Difference” to mean the distance apart two colour points must be for the colours to be just barely noticeably different.  This is the distance at which the figure-background difference just becomes perceptible by a human viewer’.
We began to realise that if we could place a digital photo of the Kabadul Kula rock wall into the computer and instruct it to recolour more blue-greenish the grey or brown (mostly background pixels), we could increase the distinctiveness of the background rock.  Likewise, intensifying the reddish colour of all pixels would affect the foreground more than the background and bring out the distinctiveness or contrast of all coloured pixels and thus coloured regions on the rock surface.
‘There are several ways to represent colours’ continued John.  ‘One way is to measure the amounts of red, green and blue in a pixel directly, so that what we measure corresponds directly to the physical light measurements made by the camera.  Another way is to focus on the hue (H), the dominant spectral wavelength of the colour; saturation (S) – that is, the extent to which other colours (such as grey) are mixed into the dominant wavelength; pure red is saturated, but pink is unsaturated because it has white, a combination of all colours mixed in – and the brightness (B) or intensity of a colour, being the total amount of incident light a colour reflects’.
‘“Contrast enhancement” is a process in which we transform the colours of all the pixels of an image to try to increase the distance between the average colour of the art (the foreground pixels) and the average colour of the background rock (the background pixels), or between adjacent paintings of different ages.  There are several ways to accomplish such enhancements, and if we do it well, we can convert differences that are not noticeably different into differences that are noticeably different.  So what seemed invisible before enhancement, becomes visible.  One way is simply to shift one or more of the basic colours of a painting, red, green or blue, away from the dominant background colours, thereby accentuating contrast.  Another way is to increase the purity of colours.  As saturation represents how much grey is mixed with a ‘pure’ colour, increasing the saturation of colours removes the impact of greys, increasing the contrast between colours in the process.  Increasing the saturation will make the slightly yellowish background pixels more yellowish, the slightly bluish background pixels more bluish and will make the slightly reddish foreground pixels more reddish’.
‘So here’s the ritual we will use to get the rock to give up its mysteries’, John concludes.  ‘First, we’ll take the pictures with the digital camera and enter them into our laptop computer using the compact flash adapter card.  Once entered, we’ll adjust the photos’ brightness and contrast to get the best picture.  This is like adjusting the brightness and contrast controls on a TV.  Next, we adjust the saturation of the image.  This intensifies the colours, making them look more distinct.  It’s like the “colour” control on a TV.  All the time we’re making these adjustments, we look at the results and try, by repeating previous steps, to get the best results.  We then adjust the hue in the image because the human eye can sometimes distinguish some colour (hue) differences better than others.  This is like adjusting the “tint” control on a TV.  Next we try to expand the contrast along the direction running between the average colours of the regions.  This is something we can’t do on a TV, but can do in some image processing programs.  Finally, we can experiment with these tool on the software, until we reach results that maximise contrast between the background rock and the foreground paintings’.
We were now at a point where, with the above knowledge, a digital camera and photo enhancement program, Kabadul Kula’s faded paintings – including the older art underlying the Kiwai headhunter paintings – could once again be seen, perhaps for the first time in hundreds of years.  We know well from ethnographic sources and current oral traditions that when European sailors began to frequent the waters of the Straits complex interactions were held between Dauan Islanders and their Papuan and Islander neighbours.  But we know nothing of the deeper antiquity of such interactions, nor of interactions with more distant lands, nor indeed of Islander cultural practices before the period of European contact.  So when Kabadul Kula’s decorated rock surfaces were enhanced and long-hidden paintings began to take shape, including images of items of material culture never before seen at Dauan, our excitement grew.  Above the dogai is a tall hut reminiscent of ethnographically documented houses from lowland Papua and the western islands of the Straits, complete with its occupant.  Shortly to the right an ethereal face, to its side a long shield (Figure 2).  The head with short, spiked hair, large concentric eyes, an outlined nose that extends across the forehead, and wide mouth with ferociously jagged teeth, has never before been recorded from Torres Strait.  Nor have shields of any kind, unknown also to Dauan’s immediate Papuan neighbours but known from canoe shields among the Kiwai and other peoples of the Fly River mouth one hundred and twenty kilometres to the east, signalling likely distant Papuan cultural influences predating the ethnographic situation.
Nearby is a masked dancer with arms spread out to the sides, bent elbows, and slightly splayed legs with large feet (Figure 3).  On its head is a fish headdress topped by a dheri, itself a traditional form of headdress worn in western Torres Strait during ritual performances.  Fish headdresses such as that painted at Kabadul Kula are well documented from ceremonies of the early contact period, and fall into various types.  They were made from panels of hawksbill turtleshell tied together with chord.  But only one example of a headdress with a full human figure mount is known from the European contact period – the ‘Iabur mask’ drawn by Joani, a Mabuiag Islander, in 1898 (Figure 4).
Joani’s drawing is a key to understanding the painted headdress at Kabadul Kula.  Both the drawing and painting reveal a large fish with fins and open mouth – pointing to the left – whose length is approximately the same as that of the height of the wearer.  The mouth in both fish images is held open by a stick and the nose of the fish is surmounted by a ‘figure called Malu’ on the drawing, while the rock painting also exhibits a nose mount, albeit of indeterminate form. While the Iabur mask is surmounted by a man ‘named Iabur’, the Kabadul Kula headdress is surmounted by the traditional feathered dheri headdress of the islands.
A significant feature of Joani’s drawing is the representational style of the wearer of the mask. The outstretched arms with bent elbows and open fingers and splayed legs with large feet and open toes are essentially identical to the style of the painted headdress wearer at Kabadul Kula. So while some of the other paintings indicate links with Papuans to the north, similarities between Joani’s and the painted masks reveal a common representational style between Dauan and Mabuiag Islanders, sixty-eight kilometres to the south. 
Below the masked dancer are smaller dancers aligned above a long, thin red line, as if on a string (Figure 5).  The two stick-figures on the left have out-stretched arms and legs.  One dancer has small tassel-like protrusions from the waist and brandishes a long, hooked object in one hand.  Another has three spikes emanating from her or his head, reminiscent of ethnographically documented feather tufts.  The three other dancers have the base of their feet resting on the single thin line. The central figure is solid infill in form, arms spread to the sides with elbows pointing upwards. Extending from its torso is a three-pronged motif much akin to the four-pronged motif extending from the figure with the fish headdress.  The two remaining figures on the right are similar in style and exhibit solid infill bodies, outstretched arms and legs, large triangular-shaped ears and large feet similar to that on the fish headdress figure. 
These design conventions are all known from an 1898 drawing by ‘Sunday of Mabuiag’. A similar artistic panel of dancers with small protrusions, aligned along a thin base line is also known from Goaribari in the Aird River delta, two hundred and ninety kilometres northeast of Dauan, and one hundred and twenty-five kilometres northeast of Kiwai Island in the only known bark painting from southern Papua (now held in the British Museum) (Figure 6).  Of interest here are the common artistic conventions between Dauan, Mabuiag and southwestern Papua almost three hundred kilometres away, representing considerably greater geographical links than previously known from headhunting raids and trade links.
Even more faded and further to the right of the dancers is another painted mask – of Papuan or Islander type – completely undetected until its enhancement (Figure 7).  To the right again appears a painting of a canoe with sail (Figure 8).  The in-curving sail suggests a ‘crab-claw’ canoe, although of this we are not certain.  Crab-claw canoes are not known ethnographically from Torres Strait, nor are they known from neighbouring regions of influence, such as the Fly River mouth.  They are, however, well known from the ethnographically documented Hiri trade region of the Papuan Gulf, over two hundred kilometres to the east.  This painting warns us to be on the lookout for other possible evidence of past long-distance Papuan Gulf cultural influences into Torres Strait.
The faded paintings at Kabadul Kula – the toothed face and shield, the dancers and masks, the clan symbols, possibly the canoe – each signals foreign and long distance cultural links, revealing Islander life as a complex matrix of local, near and distant influences long preceding the tentative first European forays into the Straits.  Through enhancement the rock-art offers us new eyes with which to see the past, a history richly populated with peoples of various cultural creeds.  The seventeenth century Spanish mariners may have come to claim new territories for the Spanish Crown, but unbeknownst to them those lands were not so much there for the taking as already widely travelled territory in an international network of cultural impacts.  The Spanish had come to discover new lands with commerce and control of the seas and the saving of souls in mind.  At Kabadul Kula, Kiwai raiders did not come to save souls, but to take them.  They over-painted the already-inscripted rock not as a simple act of decorative pastime, but as a claim over people, inscribing their own presence onto the land as a right to take in an act of imposition and appropriation.  Without digital enhancement we would have never known of the prior inscriptions, of the prior signs of distant contacts that marked Dauan as an island-in-between, long before the arrival of the Spanish in the Straits, branding the island as a hybrid province of cultural influences so close to the Papuan coast and so influenced by Papuan cultures yet so distinctively Dauan.
The Kiwai raiders came to Dauan as an island already participant in an interconnected world.  It could be visited and even claimed in moments of invasion, but it could not be conquered or controlled. In their own visions of territorial acquisition the Spanish fantasised conquest, but it was not to be.  Much like the Kiwai headhunters of Kabadul Kula fame, the Spanish mariners ventured onto seas they would neither come to possess nor readily access.  Thus the Spanish sailors who had come to take ventured back to their place of origins with diminished hopes of return.  But six years after their journey to Manila Don Diego de Prado complained to the King: ‘Your Majesty should understand that the said Pedro Fernandez de Quiros is a liar and a fraud; for, by his fault, he did not discover that which the Count of Monterey most desired, namely, the crown of the Antarctic Pole [Australia, as Terra Australis Incognita], though we were so near to it.  Nor should Your Majesty give credit to a man who suffered mutiny in his ship, such as was raised by the sailors, he having been warned.  And so they treated him as the man he is, … in whose mouth there is nought but lies, bragging, and disloyalty:  and so I advise Your Majesty to trust him as you would a clerk in a merchant ship’.  Quirós was never to sail the Pacific again for the Spanish Crown, despite proposals for further exploration.  In September 1608 the Court of Spain met to decide on Quirós’s future, and in so doing also discovered that the Straits, along with other islands of the Pacific yet to be ‘discovered’, would not so easily be taken:
And now also has been considered in the Council … the proposal made by Pedro Fernandez de Quiros, what he has gone through in the said discovery, and what he seeks in order to continue it.  And the Council, having considered the matter with the attention which its importance requires, is of opinion … that what is discovered in the Indies withdraws men from Spain, which is so short of men, as is evident, it may be feared that fresh discoveries will lead to greater injury and open a way for Your Majesty’s enemies to go to occupy them, since besides the lack of men which exists in these kingdoms for fresh conquests, Your Majesty’s treasury is so exhausted that there will be much strain in retaining what has been discovered, and the Council is not sure that with good conscience it is possible to make these conquests of heathens who neither disturb nor attack us.  That this Pedro Fernandez de Quiros has got it into his head to be a second Columbus, and seeing that from what is aforesaid his design [to discover new lands] cannot be encouraged, it is not desirable to drive him to despair on account of what he has seen and discovered, and the risk there would be that he might have recourse to Your Majesty’s enemies to occupy [the newly discovered lands] …; and therefore, taking for granted that it will be best not to discuss this fresh discovery, it is of opinion that this man being so experienced should be retained here as cosmographer in order that he may be of service in marine charts and globes, through the Council of War, … and in this way everything will be settled, namely, not to make known or publish what this man has discovered, nor to drive him to despair, and to avoid the difficulty about his giving information to the enemies of this Crown, and to retain him and get from him all the profit that may be possible in whatever may arise here in respect of his profession’.
An old proverb tells us that the real voyage of discovery consists not in seeking new lands but in having new eyes.  On the tropical island of Dauan, in the Straits through which the Spanish mariners Don Diego de Prado y Tovar and Luis Baez de Torres had come to seek new lands, we had come with new eyes with which to see, and left with new visions of Dauan’s past. 

Captions for Figures

1.	Tracing of dogai painting, Kadadul Kula.
2.	Top:  photograph of rock wall with painting of face and shield, Kabadul Kula. Bottom: the same photo digitally enhanced.
3.	Left:  photograph of dancer with fish headdress, Kabadul Kula.  Right:  the same photo digitally enhanced.
4.	‘Man wearing the Iabur mask, drawn by Joani of Mabuiag’ in 1898 (from Haddon, 1912: Fig. 257).
5.	Top:  dancers on thin red line, Kabadul Kula.   Bottom:  the same photo digitally enhanced.
6.	Bark painting from Aird River delta, southern Papua (Seligmann, 1905: 161).
7.	Right:  faded painting of Papuan-style mask, Kabadul Kula.  Left:  the same photo digitally enhanced.
8.	Bottom:  faded paintings, including canoe with sail, Kabadul Kula.  Top:  the same photo digitally enhanced.