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Reducing glare on a lightboard?

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Adam Leonard
Reducing glare on a lightboard?
on May 23, 2019 at 9:13:04 pm

Reposted from the Studio Design forum because that one seemed a little quiet, and I need an answer soonish.

So I'm working at a mid-sized university putting together a lightboard studio. It's mostly done, but we've realized that the TV facing the lightboard that we use as a confidence monitor leaves a large glare on the lightboard itself. Turning down the TV's brightness all the way leaves us with only the glare of the subjectfrom the monitor, but a) that's still more than we'd like and b) the confidence monitor is then dark to the point of only being about 50% useable.

We already have a polarizing filter on the camera. How do we reduce the glare further? This is the model of TV that we're using.

What we had been thinking about was ordering a polarizing film to put over the TV screen. Would that work, or would it not do anything, since all LCD screens already have a polarizing filter? If we do want one, what degree rating do we want it to have? The TV is directly facing the lightboard at a zero-degree angle, so we'd want a filter with a zero-degree rating, right? This part is new to me.

One tutorial said to put the monitor off to the right instead of in front of the lightboard, but that forces the subject to look off to the right constantly. We're looking to avoid that and leave the monitor where it is.

Totally different suggestions are also welcome.


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Rick Wise
Re: Reducing glare on a lightboard?
on May 23, 2019 at 9:40:38 pm

I'm confused. Students look directly at the Lightboard and behind them is a monitor? Perhaps you could sketch out the layout?

Any pola will cut light intensity. If the monitor has to face the lightboard, the only solutions I see are either tilt the monitor enough so it doesn't glare, or, as already suggested, move it to the side.

Rick Wise
Cinematographer
MFA/BFA Lighting and Camera Instructor Academy of Art University
San Francisco Bay Area
http://www.RickWiseDP.com


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Adam Leonard
Re: Reducing glare on a lightboard?
on May 23, 2019 at 9:54:16 pm

No, the way it works right now is that the camera directly faces the subject, who is behind the lightboard. The monitor is just to the right of the camera. Students aren’t actually there, this is just for online courses. I can sketch it out in Photoshop or something if it’s still unclear.

I’ll try tilting the monitor when I get back in tomorrow, but I’m not sure if the stand it’s on will allow that or not.


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Rick Wise
Re: Reducing glare on a lightboard?
on May 23, 2019 at 10:02:07 pm

So it is the instructor who looks at the monitor? How about putting it slightly below the camera and tilted up, or slightly above and titled down? What is on the monitor that the instructor needs to see?

Rick Wise
Cinematographer
MFA/BFA Lighting and Camera Instructor Academy of Art University
San Francisco Bay Area
http://www.RickWiseDP.com


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Adam Leonard
Re: Reducing glare on a lightboard?
on May 23, 2019 at 10:08:30 pm

The monitor is a live “confidence monitor” that shows the professor how their presentation is looking at that moment. I did a test run of the studio today and also learned that it’s good for knowing things like how close you are to writing past the edge of the area that’s being filmed.


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Todd Terry
Re: Reducing glare on a lightboard?
on May 23, 2019 at 10:10:49 pm

That is a puzzler.. you could try polarizing film on the monitor (in addition to the filter on your camera)... but you are right in that all LED monitors are, in theory, already polarized.

If you happen to already have two polarizing filters, you could keep one on the camera and hold the other one up in front of the monitor and see if you can find a rotation where the image completely disappears (goes dark). That would be an easy test, and would save you the expense of polarizing the whole monitor before you find that it doesn't work.

Also, keep in mind there are two kinds of polarizers... circular, and lenticular (or linear). The one on your camera is probably circular, most filters for cameras are (because you have to have a circular polarizer for things like autofocus to work). It might be the case that you get better results, in this instance, from a lenticular polarizer. It's work a try.

What would really be cool and work perfectly is something that is a lot more complicated and inventive... that'd be some kind of electronics voodoo that would "flash" the monitor on and off 24 times a second (or 30, or 60... whatever your camera frame rate is)... and have that syched with the camera in such a way that the monitor is dark during the camera exposure. That way the monitor could be as bright and angled as straight-on as you like, and never be seen by the camera at all. But we are getting into something much much more complicated there.

I've often thought that something like that would be a cool blocking/marking system on set, if you have actors that have to do complicated or exactly repeatable actions and hit marks precisely. You could have some kind of laser projector that projects spike marks and blocking lines on the set, but because they are phased on-and-off with the camera shutter speed they are perfectly visible to the actors but completely invisible to the camera. Same principal.

And Rick, click on the "lightboard" link in Adam's original post, that will show you exactly what these are and how they work.

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com



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Mark Suszko
Re: Reducing glare on a lightboard?
on May 24, 2019 at 3:08:05 pm

Enjoyed exploring the link to his rig; it is very well thought-out and looks like it can give amazing results.

Wondering if he can try tilting the lightboard forwards just a few degrees, and putting the confidence/framing monitor above the lens to make the apparent angle difference a little greater. Angle of incidence… you know the rest...

Just spitballing crazy ideas here...

Video projector on ceiling shooting down onto the floor, with a very large size. Your gaze flicks down to that. Could make a reflective screen on the floor at a shallow angle that won't catch on the vertical glass.

Or…. a second pane of first-surface glass anchored at the base of the lightboard at 45 degrees, with a flat monitor on the (black-cloth-covered) floor pointed up, makes an invisible prompter only the presenter can see. Mechanically, the extra glass would be heavy, fragile, and unwieldy to support.

But it need not be glass...

There are mylar films used for live stage "holographic" performances. They use that in a multimedia experience at the Lincoln Presidential Museum here in town, and in the correct lighting it is invisible. It needs to be held under tension in a frame but that could be very lightweight, even scaled to the size of the lightboard itself. With good depth of field control, I think his camera should shoot thru it without losing a whole f-stop, and resolution of the lightboard and presenter would still be good. The prompter could perhaps be a freestanding unit half-way between the camera and the lightboard... The benefit would be that the powerpoints and even prompter copy can all be there invisibly on the lightboard, from the POV of the presenter.
Now, the prompter layer is invisible to the camera, but the reflection back to the camera off the lightboard would maybe still be obvious... unless it was the same size as the original board?


Todd, love your concept of a temporally-offset projection system, visible to the live talent but not the camera. It's like a video version of the "interrupter gear" that enabled WW1 airplane machine guns to shoot thru the spinning propeller. Isn't this similar to the active electronic 3d visor viewing systems in theaters? This might be something easier to do with lasers and a motorized shutter stolen off those old film cameras adapted for dealing with TV CTt scan rates...


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Blaise Douros
Re: Reducing glare on a lightboard?
on May 24, 2019 at 5:23:24 pm

Leave it to this forum to invent solutions this crazy ☺

Adam, is it possible to get your camera farther back away from your subject? You may be able to solve this with simple light physics: move the camera farther away, and zoom in so that the overall FOV is narrowed, giving you more leeway to place the monitor. Tilting the light board just a couple of degrees would help, too; the direction would depend on whether you wanted it above or below the camera. I'd tilt it toward the presenter a bit, and put the monitor just below the camera's FOV. Easier than hanging it above.


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Todd Terry
Re: Reducing glare on a lightboard?
on May 24, 2019 at 5:29:47 pm

[Blaise Douros] "Leave it to this forum to invent solutions this crazy"

Hey, in my household, for almost any task I seem to find myself as the target of the following: "Is this going to take a complicated system of winches and pulleys?"

Yes, tilting the glass top-to-bottom (either way) OR rotating it a little left-to-right could easily solve the problem... if that still works logistically in the room and looks right on camera. It certainly is the easiest thing to try. Actually a side rotation would be easier than tilting it, by quite a bit.

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com



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Adam Leonard
Re: Reducing glare on a lightboard?
on May 24, 2019 at 6:51:07 pm

Yes, I like the idea of just rotating it. Especially because both the monitor and the lightboard are on stands that are on wheels, so tilting them isn't easy. I'll try a few things like that and report back when I have the chance.


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Adam Leonard
Re: Reducing glare on a lightboard?
on May 29, 2019 at 7:36:46 pm

Update: I was having mixed results with just changing the angle of the monitor, and then someone else working on the project was trying to tighten the polarizing filter and he accidentally discovered that adjusting it even a small amount will greatly reduce the glare. That got it down to almost nothing. Right now we're thinking about putting a polarizing filter on the monitor to kill off what's left.


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Todd Terry
Re: Reducing glare on a lightboard?
on May 29, 2019 at 7:50:05 pm

Sounds like that would do it. Let us know how it turns out.

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com



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Mark Suszko
Re: Reducing glare on a lightboard?
on May 29, 2019 at 8:26:35 pm

No, sorry, not nearly complex enough.


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