Universal Camouflage Pattern
The Universal Camouflage Pattern (UCP), also referred to as ACUPAT (Army Combat Uniform PATtern) or Digital Camouflage ("digicam"), is the military camouflage pattern used in the United States Army's Army Combat Uniform. The pattern was chosen after several laboratory and field tests that occurred from 2003 to 2004, although it has been established that UCP may well have been adopted without field testing against other patterns. Its pixelated pattern is a modification of the United States Marine Corps' MARPAT camouflage pattern which is similar to the Canadian CADPAT scheme.  There are several research programs underway to modify or replace the current standard issue pattern.
Initial patterns and colors
Three patterns were developed, called All Over Brush, Track, and Shadow/Line. For each pattern, there were four color combinations, which corresponded to a specific type of terrain, however, all four patterns used tan as their base color. The three remaining colors were green, brown, and black for the Woodland pattern, dark tan, khaki, and brown for the Desert pattern, light gray, medium gray, and black for the Urban pattern, and dark tan, light gray, and brown for the Desert/Urban pattern.
There were fifteen evaluations, which took place at Fort Benning, Fort Polk, Fort Irwin, Fort Lewis, and Yakima, Washington. The camouflage patterns were then rated on their blending, brightness, contrast, and detection by US Army Soldiers, during the daytime, and also at night using night vision devices.
Elimination of patterns
Following testing, the Shadow Line pattern was eliminated entirely, along with the urban and desert/urban patterns of All Over Brush. All four of the Track patterns were accepted along with All Over Brush's woodland and desert patterns.
Phase II & III
The patterns were then modified and tested alongside a newly introduced "Contractor-Developed Mod" pattern, MultiCam. Near Infrared testing determined that black, medium gray, and medium tan were the only colors that gave acceptable performance.
Phase IV (system level)
All four remaining patterns, desert Brush, MultiCam, Woodland Track, and Urban Track were then tested alongside each other in urban, woodland, and desert environments.
The desert Brush design received the best overall mean daytime visual rating. Contractor developed pattern received highest rating in woodland environments, but low ratings in desert and urban environments. Urban Track was generally the 3rd or 4th worst performer at each site, but was the best performer in nighttime environments. Infrared testing showed negligible differences in the performance of the four patterns. Natick rated the patterns from best to worst as: Desert Brush, Woodland Track Mod, Contractor-Developed Mod, and Urban Track.
The color scheme of the Army Combat Uniform is composed of a gray (officially named Urban gray 501), tan (Desert sand 500) and sage green (Foliage green 502) digital pattern. The pattern is noticeable for its elimination of the color black. Justification given for the omission of black was that black is a color not commonly found in nature, however this appeared to ignore the artificial digital nature of the design, also not found in nature. Pure black, when viewed through night vision goggles, can appear excessively dark and create an undesirable high-contrast image. This argument was not accepted by the Canadian forces or the USMC when they adopted the proceeding CADPAT and MARPAT patterns respectively.
The U.S. Army reported to the media that the basis for the UCP was the Urban Track pattern, which had been modified through the removal of black from the pattern and pixelated. Why the Urban Track pattern was used, given that it received the poorest ratings in visual detection from the Natick Soldier Center's testing, was unexplained.
Some Soldiers have reported that the pattern is less than ideal in most environments, particularly jungle and tropical terrain. As the U.S. Army is involved in the Middle East, the uniform may have been biased towards the current operating environments.
When passed by the Senate, House of Representatives Bill 2346 required the Department of Defense to "take immediate action to provide combat uniforms to personnel deployed to Afghanistan with a camouflage pattern that is suited to the environment of Afghanistan.” The Army is evaluating alternative camouflage patterns to determine if this was a necessary action. In recent tests conducted by the U.S. Army's Natick Soldier Center, results indicated that three other patterns did significantly better than UCP in desert and woodland environments. Four commercial submissions are being tested to replace UCP for Army use.
Cancellation of UCP and replacement
The United States Army is cancelling the Universal Camouflage Pattern. Army researchers are working on a new and better camouflage. Four new patterns are being tested to give soldiers different patterns suitable for different environments, plus a single neutral pattern, to be used on more expensive body armor and other gear. The selection will involve hundreds of computer trials as well on-the-ground testing at half a dozen locations around the world. The new camouflage patterns are scheduled to be put into field use by the end of 2014.
- ACU Presentation (ArmyStudyGuide.com)
- Defense Tech: Singing the ACU Blues
- New uniform details
- Dual Texure (Dual-Tex) U.S. Army Digital Camouflage History
- Engber, D. (5th of July). "Lost in the Wilderness, the military's misadventures in pixelated camouflage". State. Retrieved 27 September 2012.
- Dugas, Anabela; Kramer, F. Matthew (15 December 2004). Universal Camouflage For The Future Warrior. U.S. Army Natick Soldier Center. p. 27.
-  Universal Camouflage
- New Digital U.S. Army Combat Uniform eliminates Black in pattern
- UCP is a fiasco caused by incompetent, meddlesome political hacks
- New Army Uniform Doesn't Measure Up
- Camo Articles
- Defense Tech: New Army Camos: No Place to Hide?
- Maze, Rick (21 June 2009). "Troops in Afghanistan would get new uniforms". ArmyTimes (Army Times Publishing Company). Retrieved 13 August 2009.
- Cox, William (17 September 2009). "UCP fares poorly in Army camo test". Army Times (Army Times Publishing Company). Retrieved 17 September 2009.
- Lance M. Bacon (10 March 2012). "Army weighs 4 options to replace current camo". Army Times. Retrieved 15 March 2012.
- Eloise Lee (2 March 2012). "The Army Is Eyeing These Cool New Camouflage Patterns". Business Insider. Retrieved 15 March 2012.
- The Army’s $5 Billion New Uniform Already Being Replaced