Will 4200 Lumens be enough?

brandtryan

Member
Joined
Jan 15, 2021
Location
Indianapolis, IN
Any feedback on the following REAR projection setup would be greatly appreciated. The theatre is small - 150 capacity.

temp.jpg


Stage Dimensions:
23' wide, 27' deep, 8.5' height

I'll be projecting 1080P content that has been "letterboxed" to fill the awkward screen size (23' x 8.5', white stretched spandex). The "black bars" on top/bottom will just project onto the ceiling and floor.

It appears I have two options:

Option 1:
Use a short throw (.5 ratio) projector like the Optoma GT1090HDR ($1399). This is a "gaming" projector - but it does put out 4200 lumens (effective "ANSI" lumens more like 3800), has a 300,000:1 contrast ratio (laser model), and well, has a very short throw ratio :). This would leave a downstage acting area of approximately 8' deep, which is fine for this particular production. In this setup, the stage lights used would be more or less hitting the actors from 45deg above - sort of the classic "Rembrandt" lighting, or classic portraiture lighting. I will obviously work with the lighting designer to minimize any light coming close to the screen, and certainly avoid any lights actually hitting the screen (aside from ambient and bouncing light that is beyond my control).

I'm just hoping for an "acceptable" image - nothing spectacular, but just trying to avoid the image being washed out to an unacceptable degree. Unacceptable to me would be something like anything more than 30% washed out, if that even makes sense.

The bonus with this option: I would own the projector.

Option 2:
Rent a 10K projector (and lens) with a .78 throw ratio. This would require me to build a platform to extend the stage 4', as with the longer throw there wouldn't be enough "acting space". The stage lights would be moved for this setup, and again, would be approximately hitting the actors at 45deg.
This is a much more expensive solution - as the rental is likely going to come in around $2000 - $3000 for the short run of the production - and I have to add the cost of building the platform stage extension.

Any replies would be greatly appreciated!
 

jtweigandt

Well-Known Member
Joined
Aug 2, 2013
Location
Moline Il
These images may help you decide 39 steps. Rear projected 2000 lumen viewsonic bounced off mirror to a semi transparent scrim
Both of these images have lots of foreground lighting and pretty dark background projection. Sort of your worst case demo, but it worked
(In person was brighter appearing than picture) Use a more dense cloth rather than scrim=brighter 3000 lumen = brighter.. but you're covering more area so probably on a par brightness wise. Need to avoid ANY direct fore lighting on your screen/scrim
391.jpg
392.jpg
 

RonHebbard

Well-Known Member
Premium Member
Joined
Jun 12, 2004
Location
Waterdown, ON, CA
Any feedback on the following REAR projection setup would be greatly appreciated. The theatre is small - 150 capacity.

View attachment 21660

Stage Dimensions:
23' wide, 27' deep, 8.5' height

I'll be projecting 1080P content that has been "letterboxed" to fill the awkward screen size (23' x 8.5', white stretched spandex). The "black bars" on top/bottom will just project onto the ceiling and floor.

It appears I have two options:

Option 1:
Use a short throw (.5 ratio) projector like the Optoma GT1090HDR ($1399). This is a "gaming" projector - but it does put out 4200 lumens (effective "ANSI" lumens more like 3800), has a 300,000:1 contrast ratio (laser model), and well, has a very short throw ratio :). This would leave a downstage acting area of approximately 8' deep, which is fine for this particular production. In this setup, the stage lights used would be more or less hitting the actors from 45deg above - sort of the classic "Rembrandt" lighting, or classic portraiture lighting. I will obviously work with the lighting designer to minimize any light coming close to the screen, and certainly avoid any lights actually hitting the screen (aside from ambient and bouncing light that is beyond my control).

I'm just hoping for an "acceptable" image - nothing spectacular, but just trying to avoid the image being washed out to an unacceptable degree. Unacceptable to me would be something like anything more than 30% washed out, if that even makes sense.

The bonus with this option: I would own the projector.

Option 2:
Rent a 10K projector (and lens) with a .78 throw ratio. This would require me to build a platform to extend the stage 4', as with the longer throw there wouldn't be enough "acting space". The stage lights would be moved for this setup, and again, would be approximately hitting the actors at 45deg.
This is a much more expensive solution - as the rental is likely going to come in around $2000 - $3000 for the short run of the production - and I have to add the cost of building the platform stage extension.

Any replies would be greatly appreciated!
@brandtryan Two comments:
1; A black screen could / would be your friend, Rosco Labs Black comes to mind. Rosco Black's major shortcoming is its reduced viewing angle. Not having a balcony works in your favor, if your patron's seating area is wide, those seated far off to one side will only see their side of the screen.
2; Lighting-wise, consider lighting from the sides, both sides, shooting across stage with the spill and any shadows disappearing into the wings on the opposite side; this will let you illuminate your performers without any spill on your screen. Barn doors, 1/2 doors, and 1/2 hats, yes, even on ellipsoidals, can help in minimizing spill on your screen as can home-made donuts cut from Black Wrap.
Lighting from the front, no matter how steep the angle, floor bounce will be your enemy.

You will be totally amazed how well side lighting can work for you; using subtle variations, warm and warmer or cool and cooler will help with facial / feature modelling, minimizing a flat look, and pulling your performers closer to your patrons.
Side booms, even as short as 8 to 10 feet, can work well. Careful blocking is mandatory to minimize one actor shadowing an other, especially when couples are extremely close ( as was often the case pre Corona chaos and social distancing).
Toodleoo!
Ron Hebbard
 
Last edited:

brandtryan

Member
Joined
Jan 15, 2021
Location
Indianapolis, IN
@brandtryan Two comments:
1; A black screen could / would be your friend, Rosco Labs Black comes to mind. Rosco Black's major shortcoming is its reduced viewing angle. Not having a balcony works in your favor, if your patron's seating area is wide, those seated far off to one side will only see their side of the screen.
2; Lighting-wise, consider lighting from the sides, both sides, shooting across stage with the spill and any shadows disappearing into the wings on the opposite side; this will let you illuminate your performers without any spill on your screen. Barn doors, 1/2 doors, and 1/2 hats, yes, even on ellipsoidals, can help in minimizing spill on your screen as can home-made donuts cut from Black Wrap.
Lighting from the front, no matter how steep the angle, floor bounce will be your enemy.

You will be totally amazed how well side lighting can work for you; using subtle variations, warm and warmer or cool and cooler will help with facial / feature modelling, minimizing a flat look, and pulling your performers closer to your patrons.
Side booms, even as short as 8 to 10 feet, can work well. Careful blocking is mandatory to minimize one actor shadowing an other, especially when couples are extremely close ( as was often the case pre Corona chaos and social distancing).
Toodleoo!
Ron Hebbard
Side lighting - will absolutely be pursuing that - thank you so much for the tip! Will also look into the black screen.
 

RonHebbard

Well-Known Member
Premium Member
Joined
Jun 12, 2004
Location
Waterdown, ON, CA
Side lighting - will absolutely be pursuing that - thank you so much for the tip! Will also look into the black screen.
@brandtryan When you're cross lighting, position your sources so you're shooting straight across parallel to your screen. NOT across and slightly up stage. NO, straight across, slightly back lighting rather than leaning towards front lighting; yes, it feels contrary, but it works with only light reflecting from your performers reaching your screen from the front.
Remember, complimentary colors from opposite sides; warm and warmer / cool and cooler / warm and cool if you're feeling really radical; I once used amber and red for a dance number in Chorus Line for a different look.
Toodleoo!
Ron Hebbard
 
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almorton

Well-Known Member
Joined
Dec 17, 2014
Location
Caterham, Surrey, UK
I second this, we use relatively low power projectors a lot (although more than 4200, and front projecting) and side lighting is the order of the day. And yes, we have used ice cold from one side (L711) and warm (L154) from the other and it works really well.
 

jtweigandt

Well-Known Member
Joined
Aug 2, 2013
Location
Moline Il
Also if you buy the right series of epson and some others, they are "stackable" You bolt one right on top of the other and they have built in 2 axis keystone control so you can align and project the same image from both projectors, doubling the output. You then have the firepower of maybe 8 k lumens, and the versatility to use 2 projectors in some other project. (Disclaimer.. I have not personally done this but our next projector purchase will likely be in the stackable category)
 

ruinexplorer

Sherpa
CB Mods
Premium Member
Fight Leukemia
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Jul 16, 2005
Location
Las Vegas
Being that there are a lot of unknowns, I like to use the rule of thumb of 50-70 lumens per square foot. To determine that, you need to know what your image size will be. Since the projector is 16:9, to fill the width, your image is actually around 23x13 (losing 4.5' vertical). If you match the height that is around a 15x8.5 image (losing 8' horizontal). So, that means that you have 299 square feet or 127.5 square feet of actual image. That means that your image brightness is 16 lumens per square foot (would need to be as dark as a movie theater) compared to 37.6 lumens per square foot (possibly acceptable).
Of course, the quality of the image also depends on content. Basic brightness is only a small part of the overall image quality.
 

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