Design RGB Color Mixing w/ Ellipsoidals

[Froggy]

Hey,
I was wondering if it would be feasible to use 26/36 degree Source Fours in a cove/ catwalk position for RGB color mixing. My plan is to group the S4's into groups of 3 and gel one with a red, one with a green, and the third with a blue. I would repeat the process a few more times so I can have a left, right, and center group of light. Then, I would use these lights to mix whatever color the show at hand requires, providing a wash of color out of the catwalks. I only have 12-14 available S4's, so I am a bit limited. I think this would work, but if you all could confirm or deny my thought, that would be great. Let me know if what I'm saying even makes sense, too...

Thanks

 

[MNicolai]

The problem with RGB mixing with incandescents is that, should you find a good primary green, primary red, and primary blue, all of your focusing almost needs to be hard edges and each group of fixtures need to be as tightly packed as possible or you'll get weird shadows.

Typically, I think most LD's will agree that RGB mixing with incandescents is impractical, especially when you don't have many fixtures. You're often better off using pairs of fixtures, one cool, one warm.

 

[icewolf08]

In theory, it will work, but it will probably not look as good as you really want it to. One of the principles behind RGB mixing theory is that the source should be virtually in the same place, so you have to pack the three fixtures as close together as possible. Odds are you will never be able to get to white light even though theoretically you should by putting all three fixtures on at full.

Then of course there is the issue that you are going to use up at least nine fixtures to create a three area wash. This is relatively inefficient. It doesn't really take that long to re-color 12-14 fixtures, especially if you use them from catwalk, you will probably be better served by creating some kind of more traditional plot. I don't know how big your stage is, but for most people, having only three areas across is usually not enough. Also, is it really practical to use up all those dimmers on three areas?

Consider also that with the triple source setup you describe you will have to contend with triple shadows. Also, due to the fact that the sources can't physically be in the same place in space, you will see variations as actors move through the field, even if you lay all three fields on top of eachother. In fact, you may actually see color variation between an actor's head and feet.

It is a sound theory, but in practice you will probably not get the results you want which may lead to more headache than changing colors as needed.

 

[JChenault]

I have seen this done in a theatre I used to work in for a box boom position and, as a lighting designer, I hated it.

I could not get any real intensity from the positions. You are cutting out so much intensity with the primary colors that the light will always be too dim. ( The three lamps at full will put out about one third of the light that an open white fixture will)

It is very hard to get a reasonable amber or yellow color. It could just be the colors selected - but it is difficult to get a reasonable color.

The RBG method of mixing color does strange things to set and costume colors. If you have ( for example) a paint that is a pure secondary color ( yellow, or cyan, or magenta) it will appear dull as there is no light of that wavelength shining on it.

interestingly enough, I did not have issues with the RGB shadows mentioned by other posters.


If you want continuous, infinite color control - get come kind of CMY mixing, ( Morpheus S faders, or Wybron nexera, or the company in Florida whose name I cannot remember right now that adds four color filters to a source 4). Or if you want a softer wash , look at the Selador LED fixtures.

If you just need color, get some scrollers.

You will be a lot happier than trying to use RGB for colors.

 

[Footer]

I have done one show in all RGB. RGB Front, RGB Side, RGB Back, RGB everything. It was for a rock opera and it actually worked really well for that show. Keep in mind your never going to get a real white. Your never going to get anything in the pastels. As others have noted, your going to get some very, very, strange shadows.

Doing this in a rep plot is not at all advised. If it actually worked, everyone would do it.

 

[shiben]

We actually manage to produce decent white in a light lab doing RGB, but the problem of doing it on stage is the shadows. They are odd as heck, and unless you want that look (Footer's show probably was ok with them, one of my shows has specifically requested them), it probably will look funky. The reason Cycs work so well with RGB mixing is that A, the instruments are close enough to being at the same place that it works fairly well, and B, no shadows are gonna be cast on the cyc for the most part.

 

[Froggy]

Ok.
Thanks for the help. A day later I am realizing that RGB might not be the best idea. I think I'll try it during one rehearsal and probably end up not doing it.

Thanks to all who replied.