Vinyl to Digital
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From: Rowland McDonnell on 16 Mar 2010 17:51 Peter Ceresole <peter(a)cara.demon.co.uk> wrote: > T i m <news(a)spaced.me.uk> wrote: > > > I had one of the big 3 crt projectors here for a while but it was just > > too big to even play with in this small house. Which was a shame > > apparently because (I think I remember) that solution being less > > expensive to run from a consumables POV than any high_powered and > > expensive lamp type also about at the time (not sure what they use > > now). > > Anybody remember the original Eidophor? Huge display. Monochrome. Used a > reflecting liquid and an arc lamp. Delivered by truck... > > At the time, it was the only game in town. <http://en.wikipedia.org/wiki/Eidophor> Never heard of these before... "Eidophors used an optical system somewhat similar to a conventional movie projector but substituted a slowly-rotating mirrored disk or dish for the film. The disk was covered with a thick transparent oil and through the use of a scanned electron beam, electrostatic charges could be deposited onto the oil, causing the surface of the oil to deform. Light was shone on the disc via a striped mirror consisting of strips of reflective material alternated with transparent non-reflective areas. Areas of the oil unaffected by the electron beam would allow the light to be reflected directly back to the mirror and towards the light source, whereas light passing through deformed areas would be displaced and would pass through the adjacent transparent areas and onwards through the projection system. As the disk rotated, a doctor blade discharged and smoothed the ripples in the oil, readying it for re-use on another television frame. The Eidophor was a large and cumbersome device and not commonly used until there was a need for good quality large screen projection. This opportunity arose as part of the NASA space program where the technology was deployed in mission control." Dear god. And I used to think John Logie Baird was mad. Rowland. -- Remove the animal for email address: rowland.mcdonnell(a)dog.physics.org Sorry - the spam got to me http://www.mag-uk.org http://www.bmf.co.uk UK biker? Join MAG and the BMF and stop the Eurocrats banning biking
From: Rowland McDonnell on 16 Mar 2010 17:51 Adrian Tuddenham <adrian(a)poppyrecords.invalid.invalid> wrote: > Peter Ceresole <peter(a)cara.demon.co.uk> wrote: [snip] > >I never consciously saw the colour versions, although the thought of > >aligning a triple-projector setup sounds quite nightmarish. Let alone > >(AAAAAARRRRGH!) a colour disc system... > > I didn't realise that there had been a colour version. it must have had > three separate discs, rather than frame-sequential scanning, because the > image lag time on the oil film was quite long. Wikip says: "Later units used a CBS-style sequential color wheel, to produce red, green, and blue fields. The last models produced used separate red, green, and blue units in a single case." <shrug> Who knows? Rowland. -- Remove the animal for email address: rowland.mcdonnell(a)dog.physics.org Sorry - the spam got to me http://www.mag-uk.org http://www.bmf.co.uk UK biker? Join MAG and the BMF and stop the Eurocrats banning biking
From: Rowland McDonnell on 16 Mar 2010 18:08 Peter Ceresole <peter(a)cara.demon.co.uk> wrote: [snip] > I never consciously saw the colour versions, although the thought of > aligning a triple-projector setup sounds quite nightmarish. Let alone > (AAAAAARRRRGH!) a colour disc system... <puzzled> The great thing about a rotating colour disc to give you time-sequential colour separation is that there are no beam alignment problems. Baird had colour disc mechanical telly working well in the 1920s - different tech to generate the image-to-project, but the basic same idea at the colour end: rotating coloured thingy as a reflector to provide yer different colours for projection. I recall reading a Wireless World article on the subject - written at the time by a chap who'd seen a demo of it in operation. (I thought I put the article in my filing cabinet, but can I find it? Nope.) And it was meant to be a domestic set, so it wasn't hard to set up. 600 line colour, 1920s, colour picture comparable with cinema colour. That's the joy of projector telly, done properly. And Baird had it sorted in the 1920s. Rowland. -- Remove the animal for email address: rowland.mcdonnell(a)dog.physics.org Sorry - the spam got to me http://www.mag-uk.org http://www.bmf.co.uk UK biker? Join MAG and the BMF and stop the Eurocrats banning biking
From: Peter Ceresole on 16 Mar 2010 18:08 T i m <news(a)spaced.me.uk> wrote: > I first 'noticed' my tinnitus after a particularly fast [1] ride home > on the old Royal Enfield 350. It was into wind and I was wearing an > open faced helmet that was particularly noisy. Could have been the > final straw? Well a loud episode like that could certainly cause tinnitus in the aftermath. But especially if you were young and otherwise healthy, it would die away after a time. Once you were aware of it, though, you'd be aware of it whenever it turned up again. So to that extent, it could tip you into awareness; be the final straw. When at 16 I went rifle shooting, with Enfield No1 rifles firing military ammo, the noise was ear splitting, almost literally, and after firing 20 rounds all I could hear was a loud singing in my ears that went on for a long time, at least an hour, maybe more. During that time I was effectively deaf. The only other time I felt something as bad was much later, during the early '70s, in a weaving mill in Preston with hundreds of flying shuttles, very ancient and horribly noisy, and no health and safety rules in sight (or hearing). It was an amazing experience; the sound was a physical oppression. If I wanted to say something I'd stand inches away and shout, and they'd shout back, and basically we were both lip reading. After a while your ears went comfortably numb and the noise sort of faded. I think everybody working there was functionally deaf within a week, for the rest of their lives, and I'm certain they all had very severe tinnitus. -- Peter
From: T i m on 16 Mar 2010 18:33
On Tue, 16 Mar 2010 21:51:43 +0000, real-address-in-sig(a)flur.bltigibbet.invalid (Rowland McDonnell) wrote: >> I had one of the big 3 crt projectors here for a while but it was just >> too big to even play with in this small house. Which was a shame >> apparently because (I think I remember) that solution being less >> expensive to run from a consumables POV than any high_powered and >> expensive lamp type also about at the time (not sure what they use >> now). > >Coo! A mate, fed up with trying to run a business over here emigrated to NZ. I was chatting to another who is still happy in Canada and one I used to train with is still happily living in France. I had the offer on some of the bulky stuff he didn't want to take to NZ, this projector was one of them. > >It wouldn't surprise me: the engineers were very very keen on making the >contrast of the DMMA displays as high as possible with minimum light >leakage down the gaps around the mirrors. > >Why? > >Because that way, the DMMA chip needed less cooling... Oh, it helps >with picture quality, but cooling seemed to be what they were most >concerned with. That, and stopping the bloody mirrors sticking (van der >Waals forces, who'd've thought it?) :-) There seems to be loads of things we (still) get wrong re mirrors. Even when they are to be launched into space it seems? > >Very efficient use of the light, that way of doing things. I'm glad to see this is becoming more important these days. > >> >`Use it hard' - but how, when I'm just sat watching a demo? Well, I >> >could move my eyes. And I saw colour separation - single-beam >> >projector, displayed RGB time sequentially, and eye movement was enough >> >to make the colours visibly separate. >> >> Then in this case, moving your eyes was enough to tip the process over >> the edge of good function, for you. For the technology I was citing, >> using it 'hard' would be fast panning scenes. Not that was >> particularly hard for the cameraman, an analogue TV or us to view but >> for (some) digital kit apparently. > >Slow wide panning shots from BBC iPlayer HD streams were the ones that >my old 2.5GHz 4G5 couldn't reproduce smoothly - jerky movement, all the >time. That sounds like the one. > >My new 3.06GHz Core2Duo iMac - about the same CPU oomph but less RAM - >can do so without trouble. Ok. > >Both Macs have/had good graphics cards with stacks of RAM. > ><shrug> > >I merely note the data. Indeed. ;-) > >> >From what the engineers said to me afterwards, it was at the time one of >> >their bugbears, that problem. They wondered who'd put me up to asking >> >that particular awkward question - didn't seem hugely surprised when I >> >told 'em I'd spotted it all on my lonesome (so did a manager ask them to >> >ask the question?) >> >> You never know when a totally innocent observation can drop someone >> right in the poo. "Ere, did I see your Husband out with your daughter >> yesterday? ..." > ><grin> I don't think this was getting anyone into *trouble*, I think >they were just hoping no-one would notice this particular issue just >yet. The screen we had to watch wasn't *HUGE*, and it was quite a long >way away. Subtended rather a small angle at my eyes - reduces the risk >of experiencing colour separation, given the cause, that setup does. Ok > >It was all done (naturally) to show off this prototype tech as best as >they could manage - and I was very impressed, no doubt about it. It's nice to be in at the beginning of something. > >> Talking of demos. Whilst working for Kodak (Microfiche/film support >> tech) I was invited (by mistake probably) to some marketing champers, >> nibbles and a very clever 'video' presentation produced by >> (interestingly for me considering) a wall of Kodak Carousel slide >> projectors. The presentation was run to music and seemed to go on for >> much longer than I imagined something running from that hardware >> might. > >I'd assume that if Kodak put on a `big display using Carousel slide >projectors', they could have one running all week without either needing >to reload anything or repeat. At least, once upon a time. They probably could but there are some strange things out there in the commercial world. Like my mate who worked for Philips and they found it was cheaper to buy Philips CRTs from a dealer than an internal sale? Or buy a car made in the North of England (lots) cheaper in another part of the world, even considering the import / conversion / registration costs? > >I remember the Kodak HGVs; all carrying Kodak film, I always assumed. And spares for the kit I was maintaining. > >I nearly crashed into one on my motorcycle once, due to water in the >drum brake. You probably didn't want to do that did you? ;-) (As an aside I started my little Honda CB250 for the first time in probably 6 months. I popped the charger on only to see it show 'charged' very quickly (seconds). I turned on the fuel, pulled the choke, hit the starter and it nearly ran on the first push. The second had it running like the little sweetly it is). > >I grew up rather close to Kodak's big factory in Harrow. I wonder what >they're doing to do with it in the future? I mean, didn't that plant >get built to make film and film and more film? I don't know much about Harrow. I was based in Holborn and was a 'Walking Engineer' (their title for us before all the 'real' Engineers get excited) covering the City. We did our training in WGC. > >> I always find that sort of thing interesting, when things are made to >> do what they were never designed to do ... like the 48V / 4 motor >> (normally 12V and one) Sinclair C5 or even jet powered cycles and >> stuff. ;-) > >What do you think of this, then? > ><http://jalopnik.com/5294379/48+cylinder-kawasaki-pushes-boundaries-of-s >anity> > >(I think the url says it all) I think you are right (but that's the sort of thing I meant). ;-) (btw, that link was broken here but worked) Or this: http://www.youtube.com/watch?v=DDWqJe1dCgY Cheers, T i m |