lighting in front of seamless
Looking for some advice on how best to light something similar to the screenshot attached. It will be two talking heads, not just one. Similar gray seamless background. I've attached a pic of how I hope it might work, but I would appreciate advice from people with more experience. If you had suggestions on types of lights, I would greatly appreciate that too.
Your diagram doesn't show any fill lights or fill bounces, only keys and hairlights. When I shoot two people near each other, I try to arrange the keys to double as fills for each other. Or consider one larger, central shared softlight key for both.
You generally need more separation from the seamless than you expect. To keep shadows from being a problem, you're going to need the subject's heights plus a couple feet, in distance away from the seamless. This of course makes the seamless smaller in the overall frame, maybe too small. So often when I do this, if that's going to be the case, I replace the seamless with green screen and green paper on the floor, then make a virtual seamless in post, since I can mask-out and crop or garbage mask the edges of the set.
The spot that washes the seamless is then done in post, I get a lot of use out of the "spot" tool in FCPX for this.
One could also take a still into Photoshop and paint a set extension, then soft-edge mask it in, without going to green screen. it's just more work and less flexibility.
If you're doing a lot of slider moves, you may end up needing to motion-track the shots, though, if going green screen. One fun thing I found with the green screen alternative is, I can adjust the spacing between the two individuals after the fact, bringing them closer together or farther apart, to suit the needs of the final comp, as long as they had a -little- space between them to start with. They just each get their own layer and then it's easy.
You'll have better control and faster setup with manual iris control here, setting your F-stop where you want it, then adjusting the lights to get to where the scopes/meter/ zebra bars/eyeballs want you to be.
What Mark said.
In addition to needing more space between the talent and the seamless... to me your key positions seem very sharp and oblique. I would move them more toward the camera. I would do no more than a 45° angle on the talent, your positions are much wider than that, almost like side lighting.
I also think you need good back/side/hair/rim lighting. The example pic posted has none, and I think it sorely needs it.
You do list "less strong light as hair light" in a couple of places, but I'm not sure they are the right places or the best amount. Unless you are cross-aiming them, I'm assuming the hair light on the left is for the talent on the left. Note that is the same side as that talent's key. Usually you would do the backlight either directly in line with the talent/camera, or on the opposite side of the key. Your diagram shows the reverse of that, the backlights are on the same side as the key. That's going to be very bright, both front and back, on the same side of the talent's face... with nothing on the other side. That might be good for dramatic effect, but the pic you posted shows pretty flat lighting, so I'm guessing you're wanting bland not dramatic. This plot is not going to give you that satisfactorily, I think.
Also note that you say "LESS strong light as hair light." Don't underestimate how much is needed for backlighting. Of course it varies from scene to scene, but often times the backlight needs to be the strongest instrument in a setup, not the weakest. I always tell people to look at the wide shots on a well-lit network show, say, the standing monologue position on Fallon or Colbert, or presenters at the Academy Awards. Look at the floor, look at their feet. Invariably, their shadows are in front of them, not behind... because the backlight is the strongest instrument in the plot. Sometimes that's what you need. You might not, but I wouldn't go in with a very wimpy instrument as a backlight (or sidelight or hairlight or whatever), because it might not be enough. You can always turn an instrument down (dim it with a squeezer, or cut it wire scrims, or just move it back), but you can never get it brighter than 100%. So start with more than you need, to be on the safe side.
And I realize your drawing probably isn't exact, or to scale... but if it is in the ballpark you might have some of the background coverage issues that Mark mentioned... and actually need a backdrop that is much larger than you might be anticipating. For example, in your drawing if you shoot Talent B from the Cam B position on the slider, the seamless does not extend far enough to cover the background.
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