Military camouflage is part of the art of
military deception. The main objective of military camouflage is to deceive the enemy as to the presence, position and intentions of military formations. Camouflage techniques include concealment, disguise, and dummies, applied to troops, vehicles, and positions.
Vision is the main sense of orientation in humans, and the primary function of camouflage is to deceive the human eye. Camouflage works through concealment (whether by
countershading, preventing casting shadows, or disruption of outlines),
mimicry, or possibly by
 In modern warfare, some forms of camouflage, for example face paints, also offer concealment from infrared sensors, while
CADPAT textiles in addition help to provide concealment from
Ferret armoured car
with "Berlin camouflage" meant to hide it against that city's concrete buildings. Such terrain-specific patterns are rare.
While camouflage tricks are in principle limitless, both cost and practical considerations limit the choice of methods and the time and effort devoted to camouflage. Paint and uniforms must also protect vehicles and soldiers from the elements. Units need to move, fire their weapons and perform other tasks to keep functional, some of which run counter to camouflage.
 Camouflage may be dropped altogether. Late in the Second World War, the
USAAF abandoned camouflage paint for some aircraft to lure enemy fighters to attack, while in the Cold War, some aircraft similarly flew with polished metal skins, to reduce
drag and weight, or to reduce vulnerability to radiation from nuclear weapons.
No single camouflage pattern is effective in all terrains.
 The effectiveness of a pattern depends on contrast as well as colour tones. Strong contrasts which
disrupt outlines are better suited for environments such as forests where the play of light and shade is prominent, while low contrasts are better suited to open terrain with little shading structure.
 Terrain-specific camouflage patterns, made to match the local terrain, may be more effective in that terrain than more general patterns. However, unlike an animal or a civilian hunter, military units may need to cross several terrain types like woodland, farmland and built up areas in a single day.
 While civilian hunting clothing may have almost photo-realistic depictions of tree bark or leaves (indeed, some such patterns are based on photographs),
 military camouflage is designed to work in a range of environments. With the cost of uniforms in particular being substantial, most armies operating globally have two separate full uniforms, one for woodland/jungle and one for desert and other dry terrain.
 An American attempt at a global camouflage pattern for all environments (the 2004
UCP) was however withdrawn after a few years of service.
 On the other end of the scale are terrain specific patterns like the "Berlin camo", applied to British vehicles operating in
Berlin during the
Cold War, where square fields of various gray shades was designed to hide vehicles against the mostly concrete architecture of post-war Berlin.
Seasons may play a role in some regions. A dramatic change in colour and texture is created by seasonal snowy conditions in northern latitudes, necessitating repainting of vehicles and separate snow oversuits. The Eastern and northern European countries have a tradition for separate winter uniforms rather than oversuits.
 During the Second World War, the
Waffen-SS went a step further, developing reversible uniforms with separate schemes for summer and autumn, as well as white winter oversuits.
While patterns can provide more effective
crypsis than solid colour when the camouflaged object is stationary, any pattern, particularly one with high contrast, stands out when the object is moving.
 Jungle camouflage uniforms were issued during the
Second World War, but both the British and American forces found that a simple green uniform provided better camouflage when soldiers were moving. After the war, most nations returned to a unicoloured uniform for their troops.
 Some nations, notably
Israel, continue to use solid colour combat uniforms today.
 Similarly, while larger military aircraft traditionally had a disruptive pattern with a darker top over a lighter lower surface (a form of
countershading), modern fast fighter aircraft often wear gray overall.
Digital camouflage provides a disruptive effect through the use of pixellated patterns at a range of scales, meaning that the camouflage helps to defeat observation at a range of distances.
 Such patterns were first developed during the Second World War, when Johann Georg Otto Schick designed a number of patterns for the
Waffen-SS, combining micro- and macro-patterns in one scheme.
German Army developed the idea further in the 1970s into
Flecktarn, which combines smaller shapes with dithering; this softens the edges of the large scale pattern, making the underlying objects harder to discern.
Pixellated shapes pre-date
computer aided design by many years, already being used in Soviet Union experiments with camouflage patterns, such as "
[a] developed in 1944 or 1945.
In the 1970s, US Army officer Timothy R. O'Neill suggested that patterns consisting of square blocks of colour would provide effective camouflage.
 By 2000, O'Neill's idea was combined with patterns like the German Flecktarn to create pixellated patterns such as
MARPAT. Battledress in digital camouflage patterns was first designed by the
Canadian Forces. The "digital" refers to the coordinates of the pattern, which are digitally defined.
 The term is also used of computer generated patterns like the non-pixellated
Multicam and the Italian
fractal Vegetato pattern.
 Pixellation does not in itself contribute to the camouflaging effect. The pixellated style, however, simplifies design and eases printing on fabric.
With the birth of
sonar and other means of detecting military hardware not depending on the human eye, came means of camouflaging against them. Collectively these are known as
 Aircraft and ships can be shaped to reflect radar impulses away from the sender, and covered with
radar-absorbing materials, to reduce their radar signature.
 The use of
heat-seeking missiles has also led to efforts to hide the heat signature of aircraft engines. Methods include exhaust ports shaped to mix hot exhaust gases with cold surrounding air,
 and placing the exhaust ports on the upper side of the airframe.
Multi-spectral camouflage attempts to hide objects from detection methods such as
millimetre-wave imaging simultaneously.
Auditory camouflage, at least in the form of noise reduction, is practised in various ways. The
rubberized hull of military
submarines absorbs sonar waves and can be seen as a form of auditory camouflage.
 Some modern
designed to be quiet.
 Combat uniforms are usually equipped with buttons rather than
snap fasteners or
velcro to reduce noise.
Olfactory camouflage is said to be rare;
 examples include
ghillie suits, special garments for military
snipers made from strips of
hessian cloth, which are sometimes treated with mud and even manure to give them an "earthy" smell to cover the smell of the sniper.
Magnetic camouflage in the form of "
degaussing" coils has been used since the Second World War
 to protect ships from
magnetic mines and other weapons with magnetic sensors. Horizontal coils around the whole or parts of the ship generate
magnetic fields to "cancel out" distortions to the earth's magnetic field created by the ship.