Blanking plasma screens during blackout in a theatre

[Tom Baldwin]

The director for an upcoming show wants to use a plasma screen in a position where it will be permanently visible to the audience.

My concern is what this will look like in a blackout.

The plasmas I've seen all emit a surprising amount of light, even when fed video black - meaning that during our blackouts, there would be a horrible grey rectangle glowing away in full view of the audience.

 

Is there a solution to this? I'm guessing not, since I've seen this problem affecting large scale professional shows, but I thought I'd ask just in case.

 

It may be that we have to use video projection (and a blackout shutter), but there are sound aesthetic reasons in this case to actually use a plasma display.

 

Other background info:

Rear projection isn't an option because there's a brick wall in the way.

Suggestion of plasma rather than LCD is because of what we can easily obtain.

Image size required is not huge - 60" diagonal would be about right.

 

Thanks for your thoughts!

 

Tom

[J Pearce]

Depending on how cleanly the screen boots could you put it into standby during the blackouts? (DMX low voltage relay to a canibalised remote or a little PIC chip circuit to squirt out the right IR codes)

[back_ache]

Would it be acceptable to send a message through the serial or HDMI port to put it into standby and back on again?

[jonathanhill]

Connect it to a DMX relay rack and control the on or off via the lighting board.

 

Check out the start up sequence in relation to the input you need to use to see how unsubtle it is.

[pjrails]

Hi

 

In my experience with plasma screens I usually find that you can play with the Brightness and Contrast controls and get the screen fairly black and it is still OK for viewing your source especially using VGA input.

Lots of places seem to lift all settings for powerpoint presentations so there really bright.

 

Hope this helps

 

PJ

[smalljoshua]

Perhaps try putting some light ND Gel on it? Brings down the brightness when the screen's on too but it may be a worthy sacrifice.

 

Josh

[Junior8]

Any way to rig a simple blind of blackout material on a trick line maybe set within a frame surround? I have seen these used with motor control for similar purposes.

[livelifetotheverymax]

Do the new OLED style screens that seem to be getting banded about in consumer world have a proper black as they don't have a backlight?

[dosxuk]

Do the new OLED style screens that seem to be getting banded about in consumer world have a proper black as they don't have a backlight?

 

Yes, but a 60" OLED screen would cost enough to make even Bill Gates' eyes water.

[henny]

In the past I have put a DMX relay on the inverter supply inside the plasma so killing the backlight, or take a look at the LCD fillm that is black and goes clear with voltage appled

[dbuckley]

In the past I have put a DMX relay on the inverter supply inside the plasma so killing the backlight

 

That's the best solution in that it actually addresses the issue directly, rather than working around it, but it does require surgery.

[mumbles]

Or more easily, and to save any butchering of TVs, hire one with a RS-232 port, along with a Common Sense box from Artistic License. Programming is difficult, but not impossible, and once programmed, and on a DMX value the box will output the standby command, and on another value will switch the screen back on.

 

Much neater!

[ImagineerTom]

Electrically operated roller blinds (available "off the shelf") with a black / blackout material replacing the blind. Simple relay trigger and you've got a physical masking that ensures there's no light leak and it'll be a lot cheaper and more stable than most of the other solutions.

[AHYoung]

a quick lesson here, plasmas emit light and dont have a backlight, Lcds do have a backlight whether its a flourecsent tube or LEDS. Plasmas fed true black when properly calibrated will be nearly black as the plasma doesnt light up They dont go totally black as there is some current constantly passing through otherwise the response time from completely off to on is too slow -think of preheat on a dimmer to speed up the response of a filament lamp. with this in mind, you can ignore a lot of the advice above as the OP seems sure its a plasma not a lcd.

 

Start by calibrating it - if its still to bright on black, you need to remotely put it into standby, Id be very surprised if it didnt have a rs232 port and its very simple to send a standby code ofter blackout followed by an on command an appropriate time before, Id use a little amx / procon panel myself, but there are hundreds of little boxes out there, including DMX converters. you could even use a ir blaster based device if it doesnt have a 232 port, you could also take the luddite view as if you can turn the OSD off, you can probbably just pull the power as long as you remember it will take 10secs to fire up again

 

 

[Tom Baldwin]

Thanks all for the useful suggestions.

 

We're borrowing the display, so surgery isn't an option (even assuming it turns out to be an LCD...)

 

Interesting to know that plasmas actually can be calibrated to produce a good blackout. I suspect we'll only be able to evaluate this option, plus the cleanness with which transitions in and out of standby happen, once we can get hold of the actual unit. If we do decide to go down the RS232 route, that'd be fine. This is for am-dram, and we have an over-abundance of software engineers on the tech team.

 

Failing that, it'll have to be the physical shutter. I've got an idea how we can integrate this into the set design without it looking naff, but it'd be nice to avoid mechanical engineering if we can (see above re: software engineers...)

 

Cheers,

 

Tom