Camouflage has been used in ground combat throughout history, but primarily by hunters called to temporary military duty rather than formalized armies, against whom they often were pitted. The earliest forms – such as covering a combatant with dirt, mud, or bits of foliage – are still in use, even by the most technologically advanced militaries. But, as with all other elements of warfare, camouflage also has been and will be heavily affected by new materials and science.

It was not until the 1800s that national armies, initially troops of the British Empire in India and South Africa, began to shed brightly colored battle dress for neutral colors that would make them more difficult targets. But even limited camouflage did not become a semi-regular part of military dress until World War I. In the years between the two great wars, military leaders finally began shedding the millennia-old concept that concealment in combat was “shameful” and started looking for ways to increase warfighter survivability through combat uniforms that did not stand out from their background.

A major shift in camouflage design was developed in the late 1990s for the Canadian military: employing a computer-generated blending of pixels – essentially, square spots of varying size – that formed no specific pattern.

Three of the most influential – and diverse – factors in this effort were American author Gerald Handerson Thayer’s 1909 book, Concealing-Coloration in the Animal Kingdom, insights into how humans perceive what they see from early 20th century German Gestalt psychology, and the avant-garde work of cubist and impressionist painters. Combining the three, along with studies of the concealment methods of hunters, American Indians, and other non-European cultures, led to a far different style of battle uniform during World War II.

The online database Wikipedia http://en.wikipedia.org/wiki/List_of_camouflage_patterns offers a comprehensive, albeit unofficial, list of some 150 military, police, and related camouflage patterns used by nearly as many nations, most current or during the past two decades, but a few going back as far as World War II. That variety indicates not only local, regional, and allied influences, but demonstrates the seemingly endless search for the perfect way to achieve visual “invisibility” during military operations.

A major shift in camouflage design was developed in the late 1990s for the Canadian military: employing a computer-generated blending of pixels – essentially, square spots of varying size – that formed no specific pattern. An advancement on the basic effort to confuse an observer’s brain, variations on that theme were quickly adopted by other nations, especially for post-9/11 operations in Southwest Asia.

Most nations now employ a variety of camouflage patterns, for use in different environments (snow, jungle, desert, urban, etc.) by different groups (army, navy, air force, special forces, police, etc.). Some variations may be on the road to reversal, such as the divergence of U.S. Army and Marine Corps designs during the past decade of war in Iraq and Afghanistan. The two may come back together if they see success in recent efforts to develop a new universal pattern, enabling warfighters to wear the same combat fatigues into almost any environment (snow being a primary exception).

Camouflage does not make the wearer “invisible,” but tricks an observer’s eye and brain into failing to see a clear separation of the edges of the wearer’s profile from the colors and shapes around him. As a result, while the eye still sees the camouflaged warfighter, the brain – which processes images by filling in for the small area of color the eye actually sees – is tricked into accepting the pattern as part of the background and not as a person. It is an artificial application of what nature has provided to a wide range of animals and insects, most notably the color-changing capability of chameleon lizards and the ability of some ocean species to change shape as well as color.

MultiCam is designed to reflect surrounding colors and adapt to ambient light, allowing the wearer to continue blending into a variety of environments, including lighting and weather conditions, throughout the day.

For the United States, the newest universal pattern for ground forces is called MultiCam^®, a complex blend of seven shades of brown, tan, and green, typical in fewer combinations in previous jungle, desert, forest, and urban patterns. MultiCam is designed to reflect surrounding colors and adapt to ambient light, allowing the wearer to continue blending into a variety of environments, including lighting and weather conditions, throughout the day.

As a result, U.S. and allied soldiers, who often move from desert to wooded to mountain to village environments on a single patrol, can do so wearing the same cammies while maintaining a high level of camouflage protection.

Despite tests as far back as 2005 indicating MultiCam had advantages over other patterns, however, the United States initially rejected it in favor of the Universal Camouflage Pattern (UCP) for its Army Combat Uniform (ACU). A number of other nations, including Chile, Serbia, and Iran, followed suit.

Even so, others – including Russia, Mexico, and Australia – opted to buy MultiCam from its commercial manufacturer, Crye Precision LLC, located at New York’s Brooklyn Navy Yard. In addition – and despite some criticism of going with a pattern “rejected” by the United States – since December 2009 the U.K. has used a MultiCam derivative called the Multi-Terrain Pattern (MTP), to replace its nearly four-decade-old Disruptive Pattern Material (DPM) four-color woodland uniform and a lighter brown desert design.

MultiCam gained a second chance with the U.S. Army following a congressional mandate to find a new solution. That was based, in part, on soldier concerns about how well UCP was concealing them from the enemy and follow-up investigations that determined the existing ACU was ineffective in Afghanistan’s mountainous terrain.

In a 2009 computerized photo-simulation test conducted by defense contractor SAIC and the Army’s Natick Soldier Research, Development and Engineering Center (NSRDEC), MultiCam bested its competitors across a selection of desert, woodland, farmland, urban, and mountain settings. It significantly outscored 16 of the 17 other patterns tested and was determined to be nearly 21 percent less detectable than UCP, the second most effective multi-environment camouflage in the study.

Officials acknowledge any broad change in camouflage would be a multibillion-dollar effort, involving not only the battle dress uniform itself, but also body armor, equipment packs and pouches, helmet covers, and even camouflage coloring on rifle stocks, handgun grips, hand-held communications and data devices, etc.

As might be expected, some environment-specific desert and woodland camouflage outscored both MultiCam and UCP, as well as each other, in their respective environments, but not by wide margins.

MultiCam also outperformed UCP in separate tests by the U.S. Army Special Operations Command. As a result, some USASOC units in Southwest Asia, including Delta Force and elements of the 75th Ranger Regiment, now wear it instead of UCP in theater.

Officials acknowledge any broad change in camouflage would be a multibillion-dollar effort, involving not only the battle dress uniform itself, but also body armor, equipment packs and pouches, helmet covers, and even camouflage coloring on rifle stocks, handgun grips, hand-held communications and data devices, etc. In addition, the SAIC/NSRDEC report noted both new environments and new technology will continue to influence camouflage in the future.

“Areas of consideration for future camouflage development include the analysis of mission sets within and across environments and the study of camouflage during the soldier’s movement within operational scenarios verses the static conditions of this study,” the report concluded.

“Also, a thorough review of industry’s research and development efforts may introduce novel techniques and advances for military camouflage. For instance, the impact of new industrial capabilities, such as high speed inkjet printing, can be investigated. These capabilities may provide a faster industry response to enable rapidly deployable camouflage specific to a theater of interest.”

That report led to the Army’s selection of MultiCam for limited use. Strict rules on where, when, and by whom the new cammies – now designated Operation Enduring Freedom Camouflage Pattern (OCP) – are to be employed were laid out in an All Army Activities message issued in June 2010.

“OCP is authorized for wear in Afghanistan only. Only U.S. Army soldiers and members of other services assigned to U.S. Army units operating in Afghanistan are authorized [to wear it, including] during travel to or from Afghanistan [and] for unit ceremonial events just prior to deployment or just after redeployment,” the announcement declared, adding it also could be worn during pre-deployment training, “but only if UCP items are not available.”

The fact the same camouflage patterns are used by a widely diverse group of nations – including real or potential enemies – can be a complication during combat engagements where ground forces from opposing sides confront each other on a battlefield with no clearly defined dividing line.

In addition to those preparing to deploy, such as the 173rd Airborne Brigade, some units already in Afghanistan were nominated to receive MultiCam uniforms and equipment, but only those with more than 120 days remaining in theater.

The new OCPs use a fire-resistant fabric that has been treated with the insecticide permethrin and reinforced in various high-wear areas to meet Army-specified field durability requirements.

The fact the same camouflage patterns are used by a widely diverse group of nations – including real or potential enemies – can be a complication during combat engagements where ground forces from opposing sides confront each other on a battlefield with no clearly defined dividing line. That has been true throughout the history of camouflage – and a factor in some “friendly fire” incidents – especially with militaries often buying their preferred patterns from commercial sources rather than exclusive internal producers or distribution-restricted defense contractors.