You definitely will need to reinforce the lighting from sources other than the bare light bulb. It is human nature that our eyes are drawn to the brightest thing in the scene. If the only light source on the set is the bare light bulb, everything lit by it will be so much darker that the audience will come away from the performance having spent the time lookng at the bare light bulb, and not the performers.

Try re-enforcing the direction of the light coming from the light bulb with sources that are out of sight above the light bulb, hitting the folks being lit by the bulb. Put the 'practical' source on a dimmer, and balance the brightness of the bulb with the light hitting the performers.  Don't worry about creating lots of shadows. There should be lots of shadows in such a scene.

I am not sure putting a window in the room will improve things for you. If the director wants the "only" source of light to be the bare light bulb, adding a window will only diminish the effect of the bare bulb. If you need to fill shadows to increase definition of the room in which the interrogation is taking place, you don't need to have another obvious light source. A contrasting color (a muted blue is commonly used for such purposes, but there is no hard and fast rule here) will do the trick nicely.

I hope this helps you!

Voila! You are a lot further along with this than I sensed from your original post! I think you know exactly what you need to do!!!

My biggest concern with using lekos to create the light produced by the naked bulb is that these instruments have relatively harsh edges to them. I would suggest using diffusion to soften the edges from one instrument to the next in the semi-circle. What is the throw distance? If its not a huge amount, say less than 10 or so feet to the actors' faces, you might want to consider a different sort of instrument.

If you have a reasonable amount of overlap in your semi-circle of instruments, I don't think you will need to worry too much about the shadows thrown by the practical. You want to be careful not to light the practical fixture too much with these lights, or the audience will see right through your illusion. The use of ellipsoidal spotlights will also give you hard shadows. The use of a couple fresnels, or even PARs may give you less hard edges. You may want to try that out.

I think the greater number of shadows that are created by your semi-circle of instruments, the less potent they will be, and less noticeable. Let the spill between instruments work for you.

For color, there are no rules! I would put color in the semi-circle instruments that creates the color you want to have the audience associate with the bare bulb. If it needs to be really bright, then a less saturated warm would likely do the trick for you. When you dim the practical, it will read warmer, so you likely need to use some color in the semi-circle. R05, R08, R09, R13, etc. may be a good starting place, but certainly aren't the only choices.

What I meant by filling shadows is say you want to make the room very stark, and only lit by the bare bulb. In real life, our eyes are sensitive enough to see detail in the shadows of the dark room. On the stage, this is often not the case. If it is only lit by the single source, then the audience won't see much of anything in the shadows. When I 'fill shadows,' I light the areas that are to read as dark with a contrasting color to the highlight. If the bare bulb is a warm source (say in the realm of R09), then I would use a muted blue or other cool color (maybe R365, or R55, or R362 or even R371) to light the shadows.

Again, these colors are simply pulled out of thin air. I am uncomfortable giving you ideas like this, as this stuff is only my own opinion, and not gospel. The set and costumes should be the true guide to what colors you use.

Maybe you should try to do the opposite of what I have described here! Make the bare bulb a strange (not ordinary, expected) color, and make the contrasting color be the warmer one!  How about R87 as the bare bulb or something like R63 or R66 (you'd likely need to color the light bulb to pull this off), and use one of the colors I suggested for the semi-circle as the shadow filler. Or go totally wild, and make the shadows really saturated, such as R23, R42, etc.! Not at all realistic, but no one will accuse you of taking the safe route!

One last thought - think about how the shadowy areas around this sole light bulb change over the course of the play. Would the colors of these shadows change from late at night to early morning? Maybe you don't need a window in the set to show the dawn light. Maybe the window is in that fourth wall facing the audience, and you can change the light coming in from that window to indicate the passage of time.

Good luck!

for the B&W look  keep all the lights at the same temp. if you dimm any dim them all the same amount.  either open white or use some cinigel colours to correct the white we used rosco 3204 (because thats what we had) to increase the colour temp.  Use all the same colour gels don't mix colours as that will minimise the B&W look and make any colours in the paint costume and makup stand out more. 

we used this method in City of Angels and it seemed to work.

Edited by dmoes - 8/11/10 at 11:24am