Camouflage

Anolis caroliensis showing blending camouflage and counter-shading.

Camouflage is the method which allows an otherwise visible organism or object to remain indiscernible from the surrounding environment. Examples include a tiger's stripes and the battledress of a modern soldier. Camouflage is a form of deception.

Contents

1 Natural Camouflage

2 Camouflage in military history

2.1 Ship camouflage

3 Theory of camouflage

5 References

6 External Links

Natural Camouflage

An infant blends into the surrounding rock bed

An infant cuttlefish blends into the surrounding rock bed

In nature, there is a strong evolutionary pressure for animals to blend into their environment or conceal their shape; for prey animals to avoid predators and for predators to be able to sneak up on prey. Some animals use mimicry, seeming to be something else, such as a leaf, a stone, a twig, or a similar but more dangerous/poisonous animal. Some mimics also simulate the natural movement, i.e. of a leaf in the wind, this is called procryptic behaviour or habit. Other animals attach or attract natural materials to their body for concealment.

A few animals have "chromatic response," changing color in changing environments, either seasonally (ermine, snowshoe hare) or far more rapidly with chromatophores in their integument (chameleon, the cephalopod family).

Some animals, notably in aquatic environments, also take steps to camouflage the odours they create that may attract predators.

Aquatic camouflage also includes illumination and counter-illumination with photophores. Schooling fish may have bright distinct marking that, while poor camouflage for an individual, blends with others in a large school, making it difficult to distinguish a single fish.

Missing image
Ibexes.jpg

Countershaded Ibex are almost invisible in the Israeli desert.

Countershading (or obliterative camouflage) - different colours on upper and lower surfaces in graduating tones from a light 'belly' to a darker back - is common in the sea and on land. This is sometimes called Thayer's law, after Abbott H. Thayer who published a paper on the form in 1896.

Camouflage in military history

Successful camouflage became an essential part of modern military tactics after the increase in accuracy and rate of fire of weapons at the end of the nineteenth century. But it has been part of military action since pre-history, ever since a hunter first smeared himself with earth or clay.

Despite camouflage's demonstrated value, until the 20th century armies tended to use bright colours and bold, impressive designs. These were intended to daunt the enemy, foster unit cohesion, allow easier identification of units in the fog of war, and attract recruits. Not until these uniforms covered the bodies of men in long windrows across the battlefield was there a clear pressure for change.

Smaller, irregular units of scouts or rangers in the 18th century were the first to adopt unit colours in drab shades of brown and green. Major armies retained their colour until convinced otherwise. The British in India in 1857 were forced by casualties to dye their red tunics to neutral tones, initially a muddy tan called khaki (from the Urdu for 'dusty'). This was only a temporary measure. It became standard in Indian service in the 1880s, but it was not until the Boer Wars that, in 1902, the uniforms of the entire British army were standardised on this dun tone for battledress.

The United States were quick to follow the British, going khaki in the same year. Russia followed, partially, in 1908. The Italian army used grigio-verde in the Alps from 1906 and across the army from 1909. The Germans moved to feldgrau in 1910.

Other armies retained brighter colours. At the beginning of World War I the French experienced heavy losses because the troops wore red garance trousers as part of their uniform. This was changed in early 1915, partly due to casualties and partly because the red dye was manufactured in Germany. The French army also adopted a new 'horizon blue' jacket. The Belgian army started using khaki uniforms in 1915.

The French also established a section de camouflage in 1915, briefly headed by Eugene Corbin and then by Lucien-Victor Guirand de Scévola. The camouflage experts were, for the most part, painters, sculptors, theatre set artists and such. Technological constraints meant that patterned camouflage uniforms were not mass manufactured during WW I. Each patterned uniform was hand-painted, and so restricted to snipers, forward artillery observers, and other exposed individuals. More effort was put into concealing larger pieces of equipment and important structures. By mid-1915 the French section had four workshops - one in Paris and three nearer the front - mainly producing camouflage netting and painted canvas. Netting quickly moved from wire and fabric to use raffia, hessian, and cocoa - the integration of natural materials was always recommended.

Units of Camoufleurs who were artists, designers, or architects in civilian life were also largely used by the forces of the UK (Camouflage Section established in late 1916 based at Wimereux) and the US (New York Camouflage Society established in April 1917, official Company A, 40th Engineers set up in January 1918 and the Women's Reserve Camouflage Corps) and to a lesser extent by Germany (from 1917, see, for example, Lozenge - possibly the earliest printed camouflage), Italy (Laboratorio di mascheramento established in 1917), Belgium and Russia. The word camouflage first enter the English public language in 1917.

Camouflage added to helmets was unofficially popular, but these were not mass-produced until the Germans began in 1916 to issue stahlhelme in green, brown, or ochre. Mass-produced patterned, reversible, cloth covers were also issued shortly before the end of the war, although hand-made examples were in use from late 1914. Net covering was also examined, either fitted with natural vegetation or with coloured fabric strips called scrim.

Specialist troops, notably snipers, could be supplied with ???? of camouflage, including patterned veils for the head and gun, hand-painted overalls and scrim covered netting or sacking - an adaption of the rag camouflage used in Scotland by anti-poaching wardens, gillies, the first ghillie suits.

Missing image
HMMWV_camouflage.JPG

Two HMMWVs, one in woodland camouflage, one in desert

The first mass produced military camouflage material was the Italian telo mimetico pattern of 1929, used to cover a shelter-half (telo tenda), an idea copied by the Germans in 1931. With mass-production of patterned fabrics possible, they became far more common on individual soldiers in WW II. Initially patterning was uncommon, a sign of elite units, to the extent that captured camouflage uniforms would be often 'recycled' by an enemy. The Red Army issued "amoeba" disruptive pattern suits to snipers from 1937 and all-white ZMK top-garments the following year, but it was not until hostilities began that more patterns were used.

The Germans had experimented before the war and some army units used "splinter" pattern camouflage. SS combat units experimented with various patterns, including palmenmuster, sumpfmuster, erbsenmuster, and also telo mimetico using fabric seized from the Italians in 1943 - the Leibstandarte Adolf Hitler division often wore this pattern.

The British did not use disruptive-pattern uniforms until 1942, with the hand-painted Denison smock for paratroopers, followed in 1943 with a similar style M42 garment.

Missing image
Camouflaged_ship_c.jpg

A Royal Norwegian Navy craft, in a splinter camouflage pattern

The US Corps of Engineers began wide-ranging experiments in 1940, but little official notice was taken until 1942 when MacArthur demanded 150,000 jungle camouflage uniforms. A 1940 design, dubbed frog-skin, was chosen and issued as a reversible beach/jungle coverall - soon changed to a two-part jacket an trousers. It was first issued to the US Marines fighting on the Solomon Islands. Battle-field experience showed that pattern was unsuitable for moving troops and production was halted in 1944 with a return to standard single-tone uniforms.

With the return of war camouflage sections were revived. The British set up the Camouflage Development and Training Centre in 1940 at Farnham Castle, Surrey. Early staff included artists from the Industrial Camouflage Research Unit such as Roland Penrose and Frederick Gore, and the stage magician Jasper Maskelyne (later famous for his camouflage work in the North African campaign).

US 603rd Engineer Camouflage Battalion.

Ship camouflage

Missing image
Q-ship_dazzle_camouflage.jpg

A World War I Q-ship disguised by dazzle camouflage.

World War I also saw the advent of ship camouflage. Although most gunships were still painted a uniform grey, five schemes were approved in the United States for merchant ship camouflage. Ships without camouflage were required to pay higher war risk premiums.

Dazzle camouflage was briefly popular for ships in this period. Unlike true camouflage, the "dazzle" scheme used high contrast and confusing shapes to make it difficult for enemy forces to estimate speed and the range to the target ship — critical in the age of "dumb" gunnery and torpedoes. The effectiveness of "dazzle" is not entirely certain but it continued in use into World War II. By 1918 the British had applied various patterns to over 4,500 vessels - mainly under the directon of Norman Wilkinson (who became Inspector of Airfield Camouflage in WW II).

William MacKay, the creator of a popular scheme of camouflage approved by the Naval Consulting Board during World War I, wrote:

The structural and characteristic lines and angles of a ship can be either softened or destroyed. According as the ship is viewed through [a] red or green or blue filter the ship presents three different images and though none of them an image so definite as a ship painted with a flat pigment gray.

Theory of camouflage

Missing image
Sniper_irish_sniper_l96a1.jpg

A sniper camouflaged with a ghillie suit.

MacKay's statement above remains one of the most important elements in the theory of camouflage - an exact match with the environment's colors is less crucial than the patterning of the regions of color themselves. Ideally, camouflage should be made to break up and thereby conceal the structural lines of the object which it hides. Thus, the patterns often seen on camouflage clothing, masking cloth and vehicle paints are carefully constructed to deceive the human eye by breaking up the boundaries that define sharp edges and human silhouettes. This is called high difference or disruptive camouflage.

Similarly, a tiger's stripes, when viewed in the context of long grass or deeply shaded forest, have the same effect - making it hard to identify the tiger's shape as 'tiger!' Further, the tiger's non-stripe coloring tends to match its background of long grasses, called blending camouflage, high similarity camouflage or figure-ground blending. This mix of blending and disruptive patterns is called coincident disruption - the aim of modern military camouflage.

Coincidentally, the stark black-and-white zebra stripes, while not blending camouflage, is effective disruptive patterning - especially to the colour-blind lion. Another theory states that the zebra stripes are actually dazzle camouflage, yet another that the pattern discourages biting insects. It is believed that stripes, on all such animals, play a major role in identifying the animal to their mates.

Disruptive patterns are designed to counter certain human perceptual models. The tendency to fill in gaps between aligned, or seemingly aligned, shapes to create 'whole' objects (closure and continuity). That overlapping, or appearing to overlap, is part of grouping shapes together (proximity grouping). That similar shapes belong together, they are a coherent unit, while dissimilar shapes are parts of different units (similarity grouping) and so on.

Modern camouflage includes environment-specific patterns such as Bill Jordan's hunting-specific "RealTree" or Camoclad's similarly targeted "Mossy Oak" series, both contain more detailed visual elements than older camouflage. While these obliterative-disruptive patterns are more effective than traditional camouflage patterns, they are also very specific to an environment and season which precludes their use for military purposes. These styles were stimulated by Jim Crumley's "Trebark" design, first marketed in 1980. It should be noted that in the United States most hunted animals are colour-blind and rely on scent warnings (leading to activated-charcoal clothing from Scent-Lok).

Progress has also been made in generalized camouflage patterns as well. In 2004, the US Army joined the US Marine Corps in adopting an updated "digital camouflage" pattern to replace the traditional woodland pattern. It is termed "digital" because much of the design was done on a computer and unlike other camouflage patterns, it is blocky and appears almost pixelated.

People with maskun or other color blindness have been used to detect camouflage, because they have heightened sensitivity to visual patterns and their visual sensitivity curve is different from that of people with normal sight. Military camouflage schemes now are designed with dyes of defined spectral properties — even outside the range of visible light to avoid detection by technical means like night vision (NODs, night observaton devices) or thermal imaging devices. This idea was first trialled by the German Army in lte 1944 as the Leibermuster pattern. It has been argued that eventually the military will stop using simple visual camouflage as it is of such diminishing utility.

The opposite of camouflage is making a person or object more visible and easier to recognize, for example with retroreflectors and high-visibility clothing. There are hunting garments with bright orange patches that stand out to the eyes of other hunters, but are supposed to be a tone-match to the color-blind game animals.

Research also continues into adaptive camouflage, which is camouflage that changes to match its environment. One method of doing this is by changing the pre-made pattern, either automatically as some animals can like the octopus, or manually by reversing an article of clothing with a different pattern on either side.

True adaptive camouflage, which many would call "invisibility", is much more difficult. Such camouflage would require a high resolution display that renders thousands of different angles, depending on the position of the viewer (similar to a hologram). The display information would have to be interpolated from only a few cameras as it is impossible to have one camera per angle displayed. Additionally, the displays would have to be capable of extreme brightness to maintain their illusion during daylight.

An example of this would be the camouflage used by the alien in the movie "Predator". The banding along the sides of the predator is a realistic graphical effect that is a consequence of not rendering enough viewable angles to truly fool the eye.

While much of the display technology exists today, the capability to extrapolate, model, and render a scene at the multitude of angles required and in real time involves more processing power than could be placed inside of an object camouflaged in such a way. It may be possible, however, if real-time adaptation or a large number of viewable angles are not required, the latter of which would result in parallax errors as seen in the predator's camouflage.