Impact Lights

Hi Pooter
I came across your amazing lightshow index by chance, great to see some recognition of those of us who regularly suffered from 'lightshow finger' in the sixties! (purple finger tips resulting from staining by the inks we used, the mix always ended up as a muddy purple and took days to wash off!), and to see some good info, I always wondered who,  where and when the shows started and who first developed liquid slides.
I was at Aston University, Birmingham, England, 65 -70. (Actually I was in the Art College next door, we shared the same Students Union with the University and College of Commerce.) We had a lightshow which I ran 68 -70, generally called Impact after the Union disco. It quite likely was started by Fred Smith, (Amoeba), who was a student at Aston for a while and came back and guested now and then with his show, (he'd left the university by the time I was operating)
I took over from a fellow art student, Roger Knights (Industrial Design) who had got a lot of ideas from another ID student Bob Rickard, who did a lot of experimenting with lighting effects. Dick Martin, an architecture student was one of the mainstays at that time, but sadly failed his year and left. The other key people were Trev Brown and his girlfriend Denise and Paul Denison-Edson. Later I was joined by my girlfriend, (now wife), Cathy who was also an art student and finally Alastair ? who took the show over in 1970 when I graduated.
We did the lot, Aston was generally reckoned to have the best university lighting team in the country then. We combined conventional stage lighting with the projected lightshow. The conventional stage lights were backed up by colour wheels and rotating pattern discs, with a lot of co-ordinated colour flashing, (especially the backdrop battens and cyc troughs) controlled from the board, and a set of floods operated with a simple microswitch keyboard, (The province of Paul Denison-Edson),
We dtd a typical UK complete overlay show when working onto a stage and group, with all the projectors playing onto the same frame area, as opposed to the American montage style. (I.E.each projector covered all the screen/backdrop, not just a part of it). For discos we covered as much wall area and screens suspended above the floor area as possible, each with a single projector
Overhead projections (Mainly Trevor Brown, a sculpture student who started off doing pharmacy(!) or me) - were watch glasses, tanks, air bubbles from a fish tank aireator, oil, detergent and ink mixes, goldfish (which were quite happy in the watered down inks), etc . We had a collection of patterned base tanks and bowls etc for the overhead, but it was always a struggle to get good colour a long distance despite a powerful lamp - overheads are best suited to back projection or short throw but wide/big picture images at discos. Using the O/H with the Tutors from a stand at the back of the hall onto the stage was always a challenge and you could only use the centre of the table due to the wide angle spread of the image. I remember Fred Smith did a very nifty conversion on a Tutor 1, he converted it to a QI lamp and then sat it on its back with a mirror to get the beam horizontal to get a very powerful long range overhead in which he used watch glasses.
We used Aldis Tutor 1000watt projectors (4 eventually) for liquid slides with the heat filters removed and holes drilled in the top of the carriers so we could get a hypo in and part the slide plates from above to inject fresh ink - gave an atomic mushroom cloud effect. Sometimes we used colour wheels and distorted chequer and moire type patterns on slide glasses laced up and overprojected as well as conventional photographic slides of all sorts of images from Indian 'patterns' to 'psychedelic' images. Using strobe type wheels with only 2 or 3 colours and  blanks between them you got a flashing effect and the interaction of the colours added to it when primaries were used - reinforcing or cancelling each other. We also made up some slides using Letraset transfers of WW1 biplanes - there were a set of images, Snoopy and the Red Baron, I think, which with the strobe colour wheels flashed in and out like an early jerky movie show.
I  used a film strip carrier which had two sheets of glass which could be manipulated by holding the film spools, with a sandwich of cellophane and inks trapped between them - same principle as watch glasses on an overhead. The Tutors had zoom lenses which made it easy to size the picture in relation to the projection distance
There seems to be a widespread misunderstanding about liquid slides, they were not oil slides, oil didn't really come into it, it didn't have enough colour to project with 1000watts behind it and was far too viscous to respond. The only times I used it was a circle or cross of light oil on a plate to seperate different ink colours, though it only lasted so long before the inks and solvent broke down the barrier to mix (usually to the dreaded muddy purple!)
We used water based drawing inks - Pelikan being popular, plus Hooks and Dr Martins - I think the Hooks was actually  an aniline dye (which we also used) and gave brilliant deep colours without any muddiness. Yellow was always a very dfficult colour to get intense enough, it was often too washed out. There was a brilliant spirit based ink in red, blue and green made by Flomaster, super because you could put it with water based ink and they didn't mix whatever the temperature. It also gave a 3d layered illusion effect when projected. With a 4glass/3ink layers slide only one ink layer could be in sharp focus on the screen because the slide was too thick, so there was an illusion of depth because your brain 'saw' the other layers in focus a distance from the screen.
We also used a window cleaner on some slides, it set up a structure of very fine bubbles like a foam which then took on the colour of the ink bled into it. To get the bubbles and movement we used low boiling point solvents, sometimes preheating the slides with a hair dryer. Ether was the most active, then acetone and ether meths. We also, I now dread to say, used carbon terachloride which gave a beautiful slow bubble train across the slide and a much more lazy langorous movement. We tried formaldehyde - wilder even than ether but it broke down the pigments in the inks and sludged up the slides.
I suppose I should have started by saying that a liquid slide was made by using three or four standard 2x2 inch glass photographic slide cover  plates, which were readily available then, and could be used to mount 35mm and cut down 21/4 square slides. sometimes they were a little under size and came with mounting frames which we discarded. Medical and microscope slide plates were usually much thinner glass and far too fragile, the photographic ones were thicker and more robust, withstanding the heat from the projector and the fairly rough handling inevitable when working 'real time' on a group.
You laid them out and used an eyedropper or the similar cap on most ink bottles to put a couple of drops of ink on all but one of the plates. If 'bubble mix spray' or oil seperators were used, they went on first. Then, if using spirit ink, a few drops were added to the same plates, but different colours. finally a few drops of solvent into the ink, amount and type dependent on the type of movement and its speed required -they all produced different effects. Then pick up the clean plate and drop it onto one of those carrying ink, making sure it went down square with the other. Pick up the pair and drop onto the next ink bearing plate and continue until you had a full stack, then straight into the slide carrier. Four was the max you could get into most slide carriers still with their compression springs in place, we needed the springs to hold the set of glasses together, not wanting to rely purely on surface tension of the inks to do it. You had to be careful that there was enough ink on each plate to spread to the edges and fill it, but not spill over, otherwise there was a risk of surface tension carrying  ink over into the next compartment and mixing.
Sometimes the slides appeared to boil in time to the music, we wondered if the loud bass sounds actually did vibrate and compress the slide plates a little, but I suspect it was more of an illusion than anything. You could get a timed pulse by pressing the plates with a knife or fine screwdriver blade to the beat, but it wasn't that effective
Another reason for keeping the spring clips in the carriers and the plates tight together was any ink that did flood out obviously went down the side channels into the base of the carrier and could contaminate the slide if it got in. You also needed to be sure that the outside surfaces of the front and back plates were clean and had no ink smears on them. If they did, it dried quickly, especially the back plate next to the very hot condenser lens, and spoilt the slide.
It was best to put the darkest ink closest to the projector (and heat) to get it moving first and fastest, lightest farthest away to keep as full a cover of that colour as possible and avoid too much pure white light being projected, as that killed everything. When overlaying several slides, as we usually did on a stage show, the white light was avoided as much as possible, except in small bubbles, as it cut through any other images being overlaid. It also gave you the chance to suddenly have a massive contrast by putting in a 3plate/2colour very fast ether driven slide with a lot of very volatile white where the slide was boiling.
You had to keep the plates very clean as any old dried ink or dirt formed hot spots and black blobs in the image. Sometimes the hot spots worked well, causing a boil point and sending out a trail of bubbles that originated in the middle of the image, other times they caused the plate to crack.
Parting the plates and injecting more ink could be quite spectacular, the image was inverted, so the ink there appeared to rise and the injected ink to come up from the bottom giving the mushroom cloud effect then exploding and whamming everywhere when you pulled the hypo out and the plates slammed together. But it was risky, unless there was a decent image formed by the one or two ink compartments you didn't seperate, it could go close to a white out when the plates were parted and look awful.
Ink colour was critical too. The classic process colour primaries of cmy (didn't need the k) were too thin to project successfully, so you couldn't get the theoretical spectrum mix. Many inks were just too washed out with 1000watts behind them The tertiary colours produced by the overlaid inks limited the combinations you could use as some were awful, some reds and blues gave awful browns for example, not the expected purple. You also had to remember that you were using red/blue/yellow ink (i.e. paint and printing primaries) to create coloured light beams where the primaries are red blue and green. Put red and green light together and it's usually awful, you don't get the yellow you should, obviously that was only an issue when overlaying projected images. Red and green ink give you near black.
I specialised in 3 colour slides using blue, red and yellow (often actually sienna or burnt umber to get the intensity of colour). The end product was virtually black when all the compartments had a near full ink cover, then as each ink, (especially the blue), started to get bubbles these took on the colours of the other inks and the tertiaries,  purple, green, orange,  red, blue, yellow and pink bubbles all started to develop out of an almost black image. As the boiling picked up the action got faster, the black went and you got masses of different colours whamming around.
Just to hot things up even more we often flashed the projectors in time to the music by dropping our hands down over the lens to block the picture and then lifting. We used some mechanical strobe wheels as well. We had Meccano motors fitted to the lens barrels, driven by pots mounted into a 12 volt car battery charger for speed control, and as well used small colour wheels as described earlier. Three or four liquid slides being pulsed in and out, sometimes as singles and others as overlays on the stage backdrop over a group, all in time to the beat was quite something.
In the early days we had a motley collection of small projectors which were pretty useless, you needed the power of a 1000watt Tutor and the open accessible slide carrier between lamphouse and lens. We had one Tutor in the Union, and borrowed others from Visual Aids in the University until we were banned because of the burnt on ink stains down the front of the projectors! Then by a stroke of good luck we got 3 all at once to give a total of 4 Tutors + overhead, occasionally Carousels with photographic slides and whatever else we could muster - including a big arc lamp 16mm Hortson movie projector and a portable Filmosound,
We took the latter to one of the leading discos in the city once, when we were doing a lightshow there and stopped everything dead for several minutes because we projected a filched copy of Ed Emswiller's underground film 'Relativity' on to a screen hanging above the audience. Rapid work was instigated to get 'interruptors' into the beam and distort the image to abstract patterns! Because we were part of the Guild Technicians who did all the sound, lighting and projection work, we had access to all the films which were hired for showing, by hanging onto them for a few days we could fit them into the lightshow, sometimes backwards or upside down, usually with diffusers in the beam. But some of the old black and white ones were great as a base for overlaying liquid slides onto, we got into trouble for hanging on to Fritz Lang's Metropolis for over a month it was so good.
Tutors were hard to come by then, I think £50 was the going rate second hand, if you could find one. That was 5 weeks grant in those days! Now they're as common as hens teeth, and the slide plates as common as gold fillings in hens teeth, but I did manage to get a Tutor and a Tutor 2 a couple of years ago, purely by chance.
We did a lot of experimenting with things like dimple beer glasses with foil and coloured lighting gel filters and other things in them rotated on a record deck in front of a movie projector beam to get random effects, but it was inconsistent and the pattern was only any good at short range as the light was dispersed so much by the 'interruptors' we used. The Hortson was reasonable being about 10,000 watts equivalent. At very short range such techniques were quite effective with ordinary stage spots on a backdrop immediately behind the disco console, and backlighting translucent panels fronting it - the console base was a table from the refectory! A large colour wheel with half a dozen spots going through different parts of, all playing onto the same area gave a passable kaleidoscope substitute, and adding 2 pattern wheels or one with a fixed sheet as well gave moire effects. We also tried getting stress patterns from cellophane with plane polarised light passed through it, move and stretch the cellophane and the spectral colours were incredible, but not strong enough to project far because of the massive light loss from the polarisation. We tried making perspex tanks to sit in the Tutor slide apertures but couldn't find an effective heat and liquid proof sealant for them, the idea being to put fishtank aireator bubbles through them.
We used to borrow electronic strobes from the labs in the university and cadge dry ice from the dairy down the road. Put a strobe on billowing dry ice 'smoke' and you can get an incredible effect. Another trick was to wrap up a few small bits of dry ice, pocket them and go up to the bar for a pint. Then drop the ice into the beer and you get a foaming bubbling witch's brew, which we would then drink very nonchalantly, as if there was nothing unusual going on!
In those days there was no silicone mastic, glues were primitive, no red and blue washing up liquid, no clingfilm, self sealing bags, no frequency anaysers (at attainable cost)  and other things you can make good effects with. Second hand begged bedsheets and screens made up from end of roll newsprint cadged from the local paper were the order of the day. Because we were part of the Students Union setup, by and large we only got income from outside bookings so money was always tight, lamps for the Tutors were over £8 then.
When I see the technology available now for effects lighting it makes me drool, but all that I've seen of its use seems very mechanical and programmed. In our day it was almost all manual and very much a personal immediate response to the music, it was live and so vibrant, I think all the better for it.
It was hard work, you couldn't sit back much working on a live show, and you always had to be ready for a slide to blow out to a muddy white or die with no movement, needing an instant change. Co-ordinating the keyboard and stage lights with the projections was a critical task, Paul seemed to have an uncanny knack of knowing when to do a break and when to wind down. (The problem being that overuse of the stagelights flooded the backdrop and killed the projections) We had a great design for a light organ, to be mounted with the projectors, using multicore GPO cable to take the signal to the stage and relay units and dimmers similar to the Strand Lighting portable desk units and dimmer packs. But there were never the resources to build it, shame because Paul would really have come into his own then.
Happy days..... if only I could go back and do it all again
Hope this is of interest to you, great site
Pat Myhill 2009




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