Knud Posted May 25, 2011 Share Posted May 25, 2011 I am wondering if anyone can advise me on specifying 3 dichroic filters for a lighting installation:I am using three source four projectors to project overlapping circles of red, green and blue, the three additive primaries, so that they mix to make the three additive secondaries - yellow, cyan and magenta - and, all together, white light:http://upload.wikime...ColorMixing.png This colour wheel will be projected on light grey unpolished stone. The three projectors can be dimmed, so the installation should, theoretically, be able to reproduce any additive colour. However, there is a problem, I think: If I filter to a pure primary colours, I will be losing a lot of luminousity. I am hoping to find three dichroic filters that will give me the brightest possible circles of blue, red and green. I don't care so much about how faithfully the installation generates secondary colours. If I can produce an installation that, at maximum output, produces a colour reasonably close to white at the centre, and a bright blue, green and red at the outside, I will be a happy man. Relieved even.Can anyone advise me?ThanksKnud Link to comment Share on other sites More sharing options...
Kevne Posted May 25, 2011 Share Posted May 25, 2011 Hmmmm. I can foresee you having some problems with this project. As far as I am aware, no one makes dichroic filters for the S4. If I am correct then I'm afraid you only have a couple of opions and they are both quite expencive. If you really want to go down the filter route you would have to get them custom made. Using dichroic filters that already exist would be pointless as they wont be designed to work with the Source Four's optics (specifically colour temperature). The only other option I can think of is a natty little gizmo called a Seachanger made by Oceanoptics. Basically it's a CMYG colourchanger which is bolted into the body of a Source Four. I know this doesn't really create the effect you are looking for but it is at least food for thought. Regards, Kevin Link to comment Share on other sites More sharing options...
Neil Hampson Posted May 25, 2011 Share Posted May 25, 2011 Lee Filters do dichroic filters pre made into gel frame, I'm sure that a Source 4 is possible as I have seen them made up for Par64s on install work. have a look here:LEE FiltersYou would need to choose your colour carefully as there is not the huge range that you would find with conventional gel. G28 'Lime' is close to Lee 139, Primary green.R99 'Flame9' is close to 026 Bright RedV28 'Blueberry8' is close to 119 or 132 Dark blue / medium blue Could this be a possible application for single colour LED sources rather that conventional tungsten? Link to comment Share on other sites More sharing options...
grandMA_the_2nd Posted May 25, 2011 Share Posted May 25, 2011 Try the new Martin Mac 300 Entour - point source LED moving spotlight with dichroic colour wheel.... cheap to rent and possibly cheaper than buying custom dichroics. Link to comment Share on other sites More sharing options...
Knud Posted May 25, 2011 Author Share Posted May 25, 2011 Thanks KevinI may end up getting them custom made… By the way I should specify that the projector is the Source Four jr Zoom.Will keep researching the questionThanksKnud Hmmmm. I can foresee you having some problems with this project. As far as I am aware, no one makes dichroic filters for the S4. If I am correct then I'm afraid you only have a couple of opions and they are both quite expencive. If you really want to go down the filter route you would have to get them custom made. Using dichroic filters that already exist would be pointless as they wont be designed to work with the Source Four's optics (specifically colour temperature). The only other option I can think of is a natty little gizmo called a Seachanger made by Oceanoptics. Basically it's a CMYG colourchanger which is bolted into the body of a Source Four. I know this doesn't really create the effect you are looking for but it is at least food for thought. Regards, Kevin Thanks Neil. I'm just looking at the LEE page now. That's very useful. I don't think we'll go down the LED road because we need them to be dimmable.Thanks again!Lee Filters do dichroic filters pre made into gel frame, I'm sure that a Source 4 is possible as I have seen them made up for Par64s on install work. have a look here:LEE FiltersYou would need to choose your colour carefully as there is not the huge range that you would find with conventional gel. G28 'Lime' is close to Lee 139, Primary green.R99 'Flame9' is close to 026 Bright RedV28 'Blueberry8' is close to 119 or 132 Dark blue / medium blue Could this be a possible application for single colour LED sources rather that conventional tungsten? Link to comment Share on other sites More sharing options...
musht Posted May 25, 2011 Share Posted May 25, 2011 I don't think we'll go down the LED road because we need them to be dimmable. Er, LEDs are emminetly dimmable, Green gives you a centre around 555nm , Blue around 470 and Red would go for the 625 range. Dichro filter can be relatively cheap if your not too fussy about exact colour and can cut glass: http://www.thomann.de/gb/search_dir.html?sid=0ccb99fcc98077052cdaf23230a75b36&xsid=0ccb99fcc98077052cdaf23230a75b36&sw=dichroic&x=0&y=0 Link to comment Share on other sites More sharing options...
Knud Posted May 25, 2011 Author Share Posted May 25, 2011 KevinHad a look at the curves of the three LEE filters you recommended, and it looks like the three superimposed will giveus most of the spectrum; except there is a trough between about 580 and 610 (yellow light?). Do you think that will be a problem for the quality of the white? I don't mind if the white is a bit bluey, as long as it's just a bit.Thanks again!Knud LeeHad a look at the curves of the three LEE filters you recommended, and it looks like the three superimposed will giveus most of the spectrum; except there is a trough between about 580 and 610 (yellow light?). Do you think that will be a problem for the quality of the white? I don't mind if the white is a bit bluey, as long as it's just a bit.Thanks again!Knud Sorry! Just sent a reply to you that was meant for Neil I don't think we'll go down the LED road because we need them to be dimmable. Er, LEDs are emminetly dimmable, Green gives you a centre around 555nm , Blue around 470 and Red would go for the 625 range. Dichro filter can be relatively cheap if your not too fussy about exact colour and can cut glass: http://www.thomann.d...ichroic&x=0&y=0 Link to comment Share on other sites More sharing options...
Knud Posted May 26, 2011 Author Share Posted May 26, 2011 I think the LEE filters Neil recommended look like what I'll need. Does anyone know the exact size I need for Source Four jr? The LEE site seems to suggest 6.25" square, but it's not that clear. Also, can anyone tell me where I should order them from? They need to be delivered to Rep. of Ireland.Thanks for all your help!Knud Link to comment Share on other sites More sharing options...
Genus Posted May 27, 2011 Share Posted May 27, 2011 159mm square, which is exactly 6.25". So you're spot on. Not sure about Ireland, however Lee Filters website does list a dealer "Stage Lighting Centre" (http://www.stagelightingcentre.com/) based in Dublin. Have you tried them? Their website does list the Lee dichroic glass filters. G Link to comment Share on other sites More sharing options...
Tow Posted May 27, 2011 Share Posted May 27, 2011 'Noel' in ('noel [at] stagelightingcentre [dot] com') Stage Lighting is probably the person you want for filters.I am in Dublin and have bought from them before, however I have found them not every interested in selling a 'few bits and bobs'.For example, last year I wanted to get few pipe brackets, but after no responses to a couple of emails or any returned phone calls over a couple of weeks, I just ordered from in the UK, paid the hefty P&P charge and two days later they arrived at my door. Link to comment Share on other sites More sharing options...
Knud Posted May 31, 2011 Author Share Posted May 31, 2011 Am following all that up. Thanks for all your help.By the way, anyone have any idea how Rosco dichroic filters compare with Lee? Link to comment Share on other sites More sharing options...
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