Red, Green, & Blue Filters for Equal Luminosity

[stuckfootage]

The idea is a 3-way color key: I plan to set up three light groups
on a dancer in front of a black background. Using normal indoor 3.2K lights
and primary filters balanced for approximately equal b&w exposure,
I hope to be able to shoot in color and then produce three different versions
in black & white, using each of the three channels.
Hopefully I can then do additive comping thanks to the black background.

So by selecting which channel (r,g, or b), to use at any given edit time,
I'll be able to choose one of three different lighting setups, and
still be able to layer images. Does that make sense?

I'm wondering...how should I plan this? Do you have any suggestions
for Roscoe or Lee filters?

I know that luminosity equals .3R + .59G + .11B, so should I
look for a filter transmission ratio that is the inverse?
In other words R= 3.33, G= 1.7, B= 9; scale it by a factor
of 10 and you get R=33%, G=17%, B=90%
So maybe I should use a Roscoe 4660 red with a transmission of 39%
a Roscoe 4490 green with a transmission of 18%, and a Roscoe
No Color Blue 60 with a transmission of 62% (not quite bright enough)?

Is this the right math to get the filters in the ballpark,
assuming I'm using identical lights at the same distance?

Obviously, I will check the exposure and relative intensity after
everything is set up, but I'm trying to plan what filters to bring, etc.

Thanks for taking a moment to try to understand my idea.
Your suggestions are most welcome.

Les

 

[j]

Rosco filters will last longer than Lee, especially with the low transmission rates you want.

As for doing it in the first palce, why, whats the benefit?

 

[stuckfootage]

Rosco filters will last longer than Lee, especially with the low transmission rates you want.

Thanks for the tip!

As for doing it in the first palce, why, whats the benefit?

I plan to use the footage in a live improvised video performance.
That way, I can spontaneously decide, for example, to have the
main frontal light pulse to some beat, while the backlight can
go to some sort of slitscan distortion effect.

Another thing I might try is to set up three different backlights only,
and then I can "move" the backlight around in performance,
in order to explore the edges of the dancer's shape.

So I guess the main attraction is:
to be able to send different parts of her body to different effects,
and not to have to worry about those kinds of decisions during
the short shooting time available.

The world is full of VJs doing pulsating kaleidoscopes;
I'm trying to figure out something new.

Les