Liquid light shows (or psychedelic light shows ) are a form of light art that surfaced in the early 1960s as accompaniment to electronic music and avant-garde theatre performances. They were later adapted for performances of rock or psychedelic music.
Leading names included The Joshua Light Show /Joe's Lights/Sensefex located in NY), Tony Martin (SF, NYC), Elias Romero (SF), Mike Leonard (lights for Pink Floyd) (UK),  The Heavy Water Light Show,  Mark Boyle's Lights/Joan Hill (UK),   Lymbic System (Mark Hanau) (UK),  Glen McKay’s  Headlights, The Pig Light Show (NY),   Lights by Pablo (NY), The Brotherhood of Light (SF),  Little Princess 109 (SF),  LSD,  Ed's Amazing Liquid Light Show, Abercrombe Lights (SF),  and the Single Wing Turquoise Bird light show. (California)   
Liquid light shows surfaced on both sides of the Atlantic around 1966 and were an integral part of the Progressive music scene well into the seventies. Shows could be as simple as a single operator and two or three modified slides or overhead projectors and a couple of color wheels or as complex as shows with ten or more operators, 70 plus projectors ( including liquid slide, liquid overhead, movie and still image models plus a vast array of highly advanced (for the time) special effects equipment ).
The style and content of each show were unique but the object of most was to create a tapestry of multimedia live event visual amplification elements that were seamlessly interwoven, in a constant state of flux and above all, reflected the music the show was attempting to depict in emotional visual terms.
While the shows on both sides of the Atlantic had much in common they differed in two important ways. First, the American shows tended to be larger, with seven operators and over thirty projectors not being exceptional. In contrast, the shows in England seldom had more than three operators and ten or so projectors. Second, American shows were generally built around the overhead projector with the liquids in large clock cover glasses. Shows in England and Europe, in contrast, used modified 2" sq. slide projectors which had their Dichroic heat filters (one or both) removed and employed two layers of slide cover glasses with two liquids (oil and water based, in the early days) between each layer. Alternatively different coloured water based dyes were used in each layer, which slowly boiled producing pulsing vapour bubbles when exposed to the heat of the projector lamp with the heat filters removed. Consequently randomly pulsing and moving blobs of colour were projected on the screen creating the light show. Before the projected layers totally dried out a new slide would be switched in the projector slide holder, meanwhile the old glass would be removed, cleaned and refurbished with new dyes and the projection process would continue. The surface tension of the liquids largely retained the mixtures between the glass slides, but the process was nevertheless very messy indeed and operators had their hands almost permanently stained by the dyes. A popular choice of colored liquids for light shows was Flo-Master ink, a product developed for use in permanent marker pens. While this ink was very vivid it also had the problem of staining the operator's hands very deeply.
Two groups that are associated with the light shows they worked with above all others are Jefferson Airplane and the Headlights light show in America and Pink Floyd with light artist Mike Leonard in England. 
Light Sound Dimension (LSD) was possibly the first psychedelic lightshow and was operated by Bill Ham. Ham pioneered kinetic lighting and actually used this technique at the Red Dog Saloon back in 1965. It was also at the Red Dog Saloon where Chet Helms first met Bill and asked him to produce lightshows at the Avalon Ballroom. 
The Joshua Light Show (also known as Joe's Lights and Sensefex) located in New York was founded by a filmmaker called Joshua White. The show was the ‘house lightshow’ at Bill Graham's Fillmore East for almost its entire existence. Formed from a lighting company called Sensefex which had been started by Joshua White, Thomas Shoesmith and Bill Shwarzbach, they moved to the Fillmore and became the Joshua Lightshow. Cecily Jaffe (at that time Cecily Hoyt) had now joined the team. Later they changed their name to Joes Lights having parted company with Joshua White. A video of Joshua White at work showing how some of the effects were achieved can be found here. 
Brotherhood Of Light (SF) was formed in 1968 as a collective group of lighting and multimedia specialists. Brian Eppes, Brother Ed Langdon, Marcus Maximist and Bob Pullum gathered for the purpose of visually enhancing and augmenting the psychedelic music of the day. Unlike standard stage lighting, which was generally static and non-interactive, Brotherhood Of Light utilized liquid dyes, overhead projectors, color wheels, slide projection and 16mm film to produce not just a light show, but a live multi-sensory musical experience. The show performed at San Francisco's Winterland Ballroom and Fillmore West with such classic acts as The Jimi Hendrix Experience, The Doors, Led Zeppelin, Traffic, Ike and Tina Turner, B.B. King, Crosby, Stills and Nash, Janis Joplin, Creedence Clearwater Revival, The Who, Santana, the Grateful Dead and the Allman Brothers Band. On a typical night in 1970 you could see, The Byrds, Fleetwood Mac and John Hammond with Brotherhood Of Light providing visuals for all three bands or on a night later that year, Joe Cocker, Leon Russell and Van Morrison. They also performed at the Grateful Dead New Year's Eve shows at Winterland.
The Heavy Water Light Show (Mary Ann Mayer, Joan Chase and John Hardham, SF), did shows and album covers for Santana, the Jefferson Airplane and the Grateful Dead before moving into planetariums in the 1970s. The cover of the LP Santana III is an image (or set of images) from their show. Their work is characterized by extensive use of photographs and film sequences in addition to psychedelic oil effects.   
Mark Boyle (light show). United Kingdom . Personnel:Mark Boyle, Joan Hills, Des Bonner, Cameron Hills. Born in Glasgow in 1934, Mark was already producing art in many forms such as paintings, installations and sculptures and had many exhibitions in Edinburgh, Glasgow and London prior to getting involved with light shows. In 1966, Mark Boyle's, the Son et Lumeniere for Earth, Air, Fire and Water ran at the Cochrane Theatre, London, closely followed by the Son et Lumeniere for Insects, Reptiles and Water Creatures and the Son et Lumeniere for Bodily Fluids and Functions. These events were groundbreaking in respect of projected lighting and consisted of chemical and physical reactions projected onto a screen whilst being surrounded by various taped sounds.
Elements of this lightshow evolved and performances were made at the legendary UFO Club in London’s Tottenham Court Road. Later that year he formed the Sensual Laboratory with Joan Hills, who would later become his wife. In 1967 the first of many collaborations started with The Soft Machine, with shows at the Edinburgh Festival and in the Netherlands and France. Also in 1967 Liquid Light Environments ran at the UFO throughout the year. During 1967 Mark invented and patented a machine with a light sensitive screen that could do three colour separation on anything that was projected onto it and turn it into sounds, i.e. one colour would create one type of sound and another colour would create a totally different sound. Concerts with The Soft Machine followed in the Netherlands and again in France as well as work on the Structure of Dreams at the Arts Lab, London.
INTERGALACTIC LIGHT SHOWS by Moose & Colini's in Detroit at the Grande Ballroom and Eastown Theater. They supplied specially built projectors to other light show artists, and had over two dozen different projected effects, and were first to introduce the helium-neon laser to the art.
In 1968, the Sensual Laboratory toured in the USA and Canada with Soft Machine and Jimi Hendrix as well as staging a controversial production at London’s Roundhouse ‘Bodily Fluids and Functions. This consisted of a couple copulating on stage whilst being wired up to ECG and EEG which were projected from closed circuit TV onto a huge screen. With heartbeats and brainwaves on display, every second of the experience was shared by the audience. Also in 1968 was the Liquid Light Environment produced for the opening of the ICA ( Institute of Contemporary Arts) in London.
Glenn McKay's Headlights performed many shows with Jefferson Airplane, as well as with the Grateful Dead, and later staged shows at the Whitney Museum in New York in 1968 and in 1999 at the San Francisco Museum of Modern Art. McKay is also a painter and photographer.
The Pig Light Show (Saint Elmo’s Fire) started by Marc L. Rubinstein in 1965 as Saint Elmo’s Fire. The name was changed after (in his own words)  "a strange episode having to do with a Mothers of Invention concert at the Garrick Theatre in the Village", which resulted in Marc being given the local nickname "Pig", and the light show was known as Pig’s Light Show.
The first Pig Light Show was at the Fillmore East under the direction of Marc L. Rubinstein” with Larry Wieder on reflectives, Patrick Waters on liquids, Mark Miller at the controls and in charge of slides. Later they were joined (for a while) by, Joe Lipton, Marvin Chanes, Sandy Frank, Robert Cohen, who had had a show called London Lights.
The Single Wing Turquoise Bird lightshow troupe worked in Los Angeles and Venice, California. Famous for their wide screen lightshows at the Shrine Exposition Hall in Los Angeles in 1967 and 1968, and later for their series of evocative multimedia performances at various venues, most notably in the Cumberland Mountain Film Company studio in the loft above the Fox Venice Theatre, 1970 - 1975. They did lightshows for The Chambers Brothers, Velvet Underground, Grateful Dead, Big Brother and The Holding Company, Pacific Gas & Electric, Steve Miller Band, Taj Mahal, Dr. John, Sons of Champlin, BB King, The Yardbirds, Pinnacle, Traffic, and Quicksilver Messenger Service.
Elias Romero light shows featured Elias Romero and Ray Andersen (who was also the manager of The Matrix at the time). Although he never went on to work the ballrooms, Romero was a long-time "light artist" with his own distinct approach utilising a unique, all-liquid show. Famous shows include the 9 March 1966 Big Brother and the Holding Company show at the Firehouse, 3763 Sacramento Street, San Francisco. 
Little Princess 109 became the house light show for Bill Graham Presents in 1968. Little Princess 109 worked at Fillmore West and Winterland continuously from December 1968 until Fillmore West closed in July 1971. According to the records of the Bill Graham Presents archives, they worked for Graham longer than any other light show, and performed more nights of light than any show for the entire Fillmore/Fillmore West/Winterland period. 
Tony Martin began providing a visual component to avant-garde electronic music performances of the San Francisco Tape Music Center, and later mounted the first Fillmore West lightshow, Electric Circus, NYC design and perform-1967-70; 2010:lightshow at The Boiler, NYC.
Abercrombe Lights were formed in 1966 and did many shows at Bill Graham’s Fillmore Auditorium. The man behind it all is George Holden, who is still very much a key player on the Bay Area lighting scene. Abercrombe Lights lit most of the SF bands over the years including the Grateful Dead, Country Joe and The Fish and Jefferson Starship. 
Liquid Light Lab is a contemporary psychedelic light show, active in the United States. It is the work of Steve Pavlovsky, an artist and musician from New York City. Liquid Light Lab began projecting in 2008, has performed hundreds of shows and worked on numerous music videos and art installations. Notable collaborations include work with Columbia Records, Sony Music Group, High Maintenance on HBO, and Alex Grey's CoSM. Accompanied musicians have included the 13th Floor Elevators, Joe Russo's Almost Dead, The Zombies, Gene Ween, The War on Drugs, Roky Erickson, and The Jon Spencer Blues Explosion, The New Riders of The Purple Sage, and Antibalas.
Steve Pavlovsky / Liquid Light Lab is also notable for producing tutorial videos on liquid light shows, maintaining a light show history blog, and offering art supplies to other artists.
Ed's Amazing Liquid Light Show (2012) is a young artist-collaboration based in Amsterdam. Ed's Amazing Liquid Light's core businesses are: Performing Liquid Light Shows, making Liquid Light video's for various purposes  and producing Liquid Light Art. Liquid Light Art is the art of shooting, editing and presenting stills from a liquid light show in High Definition. 
Diogenes Lantern works A classic liquid light show was provided at Chet Helms' (Avalon Ballroom, San Francisco) "Denver Dog / Family Dog" in Denver in 1967.