Solarisation (or solarization) is a phenomenon in photography in which the image recorded on a negative or on a photographic print is wholly or partially reversed in tone. Dark areas appear light or light areas appear dark. The term is synonymous with the Sabattier effect when referring to negatives, but is technically incorrect when used to refer to prints^{[citation needed]}.

In short, the mechanism is due to halogen ions released within the halide grain by exposure diffusing to the grain surface in amounts sufficient to destroy the latent image.

Initially, the term solarisation was used to describe the effect observed in cases of extreme overexposure of the negative in the camera. Most likely, the effect was first observed in scenery photographs including the sun (e.q. sol, sun). The sun, instead of being the whitest spot in the image, turned black or grey. See Minor White's: The Black Sun 1955

The solarisation effect was already known to Daguerre and is one of the earliest known effects in photography. John William Draper was the first to call the overexposure effect solarisation. Already in 1840 observed J.W.F. Herschel the reversal of the image from negative to positive by extreme overexposure. L. Moser reported in 1843:"....., that the light in the camera obscura produces at first the well known negative image; with continued action of the light the image turns into a positive image.... and recently I have obtained in fact on occasion a third image which is negative". (German)

William C. Cobham (born May 16, 1944 in Panama) is a Panamanian American jazz drummer, composer and bandleader, who permanently relocated to Switzerland during the late 1970s.

Coming to prominence in the late 1960s and early 1970s with trumpeter Miles Davis and then with Mahavishnu Orchestra, Allmusic's reviewer claims Cobham is "generally acclaimed as fusion's greatest drummer with an influential style that combines explosive power and exacting precision.

Born in Panama, Cobham's family moved to New York City during his early childhood. A drummer from his youth, Cobham attended New York's High School of Music and Art, graduating in 1962.

He played in a U.S. Army Band from 1965 to 1968. Following his discharge, Cobham joined an ensemble led by pianist Horace Silver for about a year, also playing or recording with saxophonist Stanley Turrentine, organist Shirley Scott, and guitarist George Benson.

Cobham branched out to jazz fusion, which blended elements of jazz, rock and roll and funk, playing and recording with the Brecker Brothers (notably in their 1970-founded group Dreams), and guitarist John Abercrombie, before recording and touring extensively with trumpeter Miles Davis. Cobham's work with Davis appears on A Tribute to Jack Johnson, among other recordings. Cobham is also one of the first drummers to play open-handed lead: a drummer that plays on a right-handed set but leads with his left hand on the hi-hat instead of crossing over with his right (and also has his ride cymbal on the left side, instead of the traditional right). He typically plays with multiple toms and double bass drums and was well known in the '70s for his large drum kits.