Design Cyc Color Wash using Fresnels

[jack63ss]

I have a 15'x40' white muslin cyc that I need to light for a community theater group. I would like to be able to switch between 2-3 colors but do not have much of a budget to buy new equipment. I have a fair number of fresnels, mostly Altman 65Qs (mix of BTN & BTL), so I am trying to figure out if I can do this using them. The specs on them say using Flood Focus you can get a 14' diameter circle at 10' distance with 88fc (btn) or 57fc (btl). I understand most of the theory in figuring out the coverage, so now to the questions.

First, how much overlap is required between the beams to make the effect look constant across the cyc, so it looks like one continuous color ? If I set it up so that the outside edge of the beam hits the center point of the beams it is adjacent to (basically overlapping circles), is that going to work ? Or could I make it work as well with less, since that would require at least 10 fixtures per color ?

Second, should I light the whole cyc from above or should I light the bottom half from ground level ?

Thanks
Jack

ps I actually have a third question, but it is a general opinion question about cyc lighting, so I think I'll put it in a separate post.

 

[derekleffew]

While the Fresnel spotlight is a very versatile instrument, if the goal is to create a seamless, even wash, it is probably not the best choice. First, unless the fixture is perpendicular to the surface being lighted, the pool will not be circular, but elliptical, parabolic, or hyperbolic, depending on the angle of elevation.

Conic Sections
Also, the beam will always be brighter, due to the Inverse Square Law, nearer the unit. Thus all the recommendations in the other thread http://www.controlbooth.com/forums/lighting-electrics/30705-best-way-light-cyc.html#post271765 for an asymmetric reflector cyclight.

However, if all you have available is Fresnels, one way to use them would be to remove the lens, thus turning the fixture into a scoop floodlight. I'd guess you'd need at least seven lights, evenly spaced across the 40', at least 5' DS of the cyc, and trimmed 3-5' higher than the 15' height, to reduce scalloping.

Now, there's no law or rule that says a cyc MUST be evenly illuminated, and from a design standpoint, a mottled, varigated sky is more visually interesting. I've worked with several designers who would mix ERS s, Fresnels, and other units in with the cyclights, or light the entire thing with out of focus gobo s.
.

 

[jack63ss]

Thanks. What you said was what I experienced the last time I tried it with fresnels. I used a couple of fresnels and 2 scoops, but it just didn't look right. And from the responses I have gotten so far I am not going to get it to work right with fresnels. Fortunately I found out from one of the other lighting designers in town (that is also on CB) that he has 2 2circuit cyc lights that we can use. Between those, the scoops And the fresnels we should be able to make it work.
Again, thanks for the feedback.
Jack

 

[jglodeklights]

I also recommend prepping yourself with some Rosco 104, 3011, 3015 and 113 or similar from other manufacturers on hand. These diffusion gels, often referred to as silks, spread light along one axis, the one opposite to how the lines in the gel run. This is useful for elimating the scallop between cyc units that can't be placed far enough away from the cyc. Or in making fixtures that spread evenly in 360 degrees not do so, thus blending better in the overap between them.