Camouflage

Camouflage is the art of hiding an individual or object from plain sight by utilising technological or natural means. This is done through the use of any combination of materials, colouration or illumination for concealment, either by making a person or object difficult to see (crypsis), or by disguising them as something else (mimesis). A third approach (motion dazzle) confuses the observer with a conspicuous pattern, making the object visible momentarily harder to locate. It is often used by the military forces of the various intelligent species of the Milky Way Galaxy.

History
Camouflage was first practiced in simple form in the mid 18th Century by rifle units. Their tasks required them to be inconspicuous, and they were issued green and later other drab colour uniforms. With the advent of longer range and more accurate weapons, especially the repeating rifle, camouflage was adopted for the uniforms of all armies, spreading to most forms of military equipment including ships and aircraft. Many modern camouflage textiles address visibility not only to visible light but also near infrared, for concealment from night vision devices. Camouflage is not only visual; heat, sound, magnetism and even smell can be used to target weapons, and may be intentionally concealed. Digital camouflage applies patterns made of pixels, often designed to disrupt outlines at different distances, providing a degree of scale invariance.

Physical Camouflage
The majority of camouflage methods aim for crypsis, often through a general resemblance to the background, high contrast disruptive colouration, eliminating shadow, and countershading. This physical camouflage helps to conceal or break up the easily recognisable outlines of enemy forces.

Imperium of Man
The camouflage utilised by the Imperium of Man is based on physical paint schemes, many of which are "Codex Approved" schemes that will be utilised by Imperial Guard Regiments and Space Marines Chapters. The schemes depend on the environment in which they will be fighting. As some planets have very different ecologies and geologies and enviroments, some of the colours used in these schemes would seem quite garish to modern eyes. Some Chapters of the Space Marines adopt a no camouflage rule, instead adopting an honorable attitude similar to 18th Century Terran armies of the 2nd Millennium, hoping to intimidate their opposition.

Orks
The Orks tend not to use camouflage, with two notable exceptions: the first is that of the Blood Axes clan who imitate the culture of the Imperium but do not understand the theory of camouflage and instead use combinations of colours and patterns with little relation to the environment in which they will be fighting, although it can sometimes prove effective. The second exception is that of Ork Kommandoz, those Ork Boyz who are "kunning az Mork", and are adept infiltrators and saboteurs, and use camouflage, misdirection and discreet movement with an aptitude baffling for such brutish creatures.

Tau
The Tau use patterns of phyical camouflage as well as flat colours to match ambient environmental backgrounds.

Necrons
The Necrons are not known to utilise camouflage patterns.

Tyranids
The Tyranids are not known to utilise physical camouflage.

Holographic Camouflage
Some races use holographic technology to either completely conceal or disruptive patterns to dazzle or confuse the viewer. Typically the Eldar and Dark Eldar use holographic technology on their vehicles and starships while the Harlequins utilise personal holographic technology. Cameleoline cloaks are used by a number of races to provide camouflauge for their elite infantry.

Natural Camouflage
Some races have specific troop types that are able to physically alter their forms (eg. the Imperial Officio Assassinorum's Callidus Temple Assassins or their colouration (eg. Tyranid Lictors).