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Design Issues and Solutions CYC color mixing- CMY, RGB, can I use both???

Discussion in 'Lighting and Electrics' started by stoteg, Apr 9, 2009.

  1. stoteg

    stoteg Member

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    Hey everyone. New dudes first question. I'm a 2nd year lite student from north florida. I'm designing for a dance piece at school, everything about the show is created in house, so each lighting student gets a piece. We're submitting the colors we want on the cyc tomorrow. I don't know how far apart they are, but the RP screen will be DS of the cyc with sky units and ground rows focused on the cyc. If they're the same units we used last year, we have 1kw Sky Cyc and 2kw Ground Rows. We have to pick 3 sets of color for both unit sets, 6 total.

    I'm just discovering color theory and I'm trying to get a grasp on it. Can I use a subtractive mixing process with CMY gels in the ground rows and an additive mixing process with RGB gels in the sky (or vice versa)? Has anyone tried to combine these systems? Should I just stick with CMY?

    And does the fact that magenta has both red and blue wavelengths in it make it mix well with both red and blue, as well as green and yellow/amber (since red and green wavelengths make up yellow/amber)?

    Last one, saw this in a really old similar thread and wanted to know more:

    What does he mean and how does it do this? Does it require computer precision to do or can you do it at the board? If I remember right last year we had put this ugly green up on the cyc and I don't remember anyone being able to make great use of it. Then again I am slightly colorblind and ALL the colors we picked last year sucked.

    Whew. I'm done. Hope I made sense. All help is much appreciated!
     
  2. beltsvillecrucib

    beltsvillecrucib Member

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    Subtractive mixing is based upon the principle that light is coming from a single source. To use CMY color mixing it is usually in the form of moving dichroic plates or gel strings. With ground rows and sky cycs you will dropping one frame of color; stick with additive. Subtractive would simply not work. Go RGB and if you want add in an amber.
     
  3. icewolf08

    icewolf08 CBMod CB Mods

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    Lets start with a quick overview of things. Using gel in general is a subtractive process. Each fixture outputs near full spectrum white light. When you put a gel in the beam, it only allows certain wavelengths of light to pass, the rest are absorbed. So you are subtracting certain colors from the light.

    As you may already know, the RGB (Red Green Blue) color mixing system is an additive process. This is similar to how your television and computer display work. You start with three separate sources focused at roughly the same place, one in each color. In a perfect world, when you run all three at full you get white. At other levels you can mix to make a near infinite color palette.

    CMY (Cyan Magenta Yellow) color mixing is a subtractive process. This process became a big hit with the advent of moving lights. CMY mixing requires starting with a single, full spectrum source. Using color filters you subtract varying amounts of CMY to mix the colors you want. If you were to roll all three wheels to full you would get no light out of the fixture.

    SeaChanger added the xG (extreme green) wheel to their product because it helps achieve some deeper colors especially in primary colors. By the same token, many manufacturers of LED lights (an additive fixture) have added an amber in addition to the RGB to help make a more natural looking white. In fact, many lighting designers choose to use RGBA n 4-cell cyc fixtures.

    So, you can put CMY colors in cyc units, but you will not be able to mix the same range of colors that you would if you used RGB. This is because you are inherently trying to utilize an additive process when you are using multi-cell fixtures. You might get some interesting colors, but probably not what you are looking for.
     
  4. David Ashton

    David Ashton Active Member

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    Using primary colours, you lose about 80% of your light before you start, added to that as you dim down the lamps the blue end of the spectrum disappears, so use the lightest colours you can, to get the most light through, magenta, amber, blue-green and medium blues are all worth considering, but it is much better to choose colours for a piece than trying for a generic, do everything, rig.
     
  5. stoteg

    stoteg Member

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    ahhh right on thanks guys
     
  6. Footer

    Footer Senior Team Senior Team Premium Member

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    I have done completely CMY plots before. It can do some interesting things, but for a cyc it "goes to white" WAY to fast. You have to really watch your levels or you will end up with no color before you know it. When I did it we used the 90 vareiety of the rosco cal-colors.
     

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