# Will 4200 Lumens be enough?



## brandtryan (Mar 11, 2021)

Any feedback on the following REAR projection setup would be greatly appreciated. The theatre is small - 150 capacity.




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!


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## jtweigandt (Mar 11, 2021)

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


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## jtweigandt (Mar 11, 2021)

Brightly lit lobby Front projected to painted wall epson 3000 lumen with about 18 feet throw.


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## RonHebbard (Mar 11, 2021)

brandtryan said:


> Any feedback on the following REAR projection setup would be greatly appreciated. The theatre is small - 150 capacity.
> View attachment 21660
> 
> 
> ...


 *@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


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## brandtryan (Mar 11, 2021)

RonHebbard said:


> *@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.
> ...


Side lighting - will absolutely be pursuing that - thank you so much for the tip! Will also look into the black screen.


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## brandtryan (Mar 11, 2021)

jtweigandt said:


> Brightly lit lobby Front projected to painted wall epson 3000 lumen with about 18 feet throw.View attachment 21663


This is encouraging! With 4200 lumens and a 11' throw, and way less ambient light .... just might work - especially if I utilize "side" lighting per suggestion from RonHebbard.


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## RonHebbard (Mar 11, 2021)

brandtryan said:


> 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 (Mar 11, 2021)

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.


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## RickR (Mar 11, 2021)

And a dark, matte floor!


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## jtweigandt (Mar 12, 2021)

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)


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## ruinexplorer (Mar 14, 2021)

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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## brandtryan (Jun 18, 2021)

Hi All - did a tech demo and the rear projected image looks pretty good -- well, certainly "acceptable" for the venue (community theatre).

I did have one question regarding my screen (spandex): I need to cut and sew it. The guy who created the projected content told me to have the seam "flap" facing the audience (and to make it is small as possible) - I suppose because if it were on the back of the screen, the light could bounce in weird ways off of those seam flaps.

I'm just wondering what kind of thread to use to sew it? I have a friend helping me sew it, but they need to know what kind of thread to use.

Thanks for any replies! Showtime in 3 weeks!!

Brandt


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## jtweigandt (Jun 18, 2021)

what size is your screen? Remember you will be better off even with 2 seams if you can put the widest field center and avoid a seam there. This would apply to either vertical or horizontal seams. A center seam will immediately draw the eye whereas a high or low one, or 2 offset verticals will more likely be forgiven. Rose Art made me a large lycra containing piece for a cyc.. and had some material that was if I recall 14 foot wide.. So we have a seam for enough material to feed onto the roller but it's never visible.


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## brandtryan (Jun 18, 2021)

Screen is 23'6.5" x 8'1"
I have 6 yards of 120" spandex

So I'm 5.5 ft short on the width and 2ft too tall on the height. Oh man, already have a headache. I'll have to cut the extra 2ft from the top and make 3 vertical strips 8' tall.

Any idea on the thread to use?


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## jtweigandt (Jun 18, 2021)

so you have almost 2 feet to play with on the top... call it 18 inches for safety. so you can make a hem for grommets. cut off the top 18 and re orient those 90 degrees 
for side strips.. 6 yards is 18 feet.. 18 inches on each side adds 3 feet.. that gets you out to 21... Nearly seamless center, and then just pull in the black curtain and give up on the full 23' 6" ... aint nobody gonn miss 1 foot 3" on each side that you masked out, and you have essentially a seamless screen where it counts, and a couple vertical seams way out to the side. The next designer will thank you and will probably just mask the sides on it's next use. Dont know what thread.. probably whatever a seamster/seamstress would normally use so the lycra can still stretch some. That's probably more important than the light transmission properties. Someone at Jo Anne fabric or the like could advise better than me.. Also simple zig zag allows for stretch on a seam.. rather than a straight stitch


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## brandtryan (Jun 18, 2021)

jtweigandt said:


> so you have almost 2 feet to play with on the top... call it 18 inches for safety. so you can make a hem for grommets. cut off the top 18 and re orient those 90 degrees
> for side strips.. 6 yards is 18 feet.. 18 inches on each side adds 3 feet.. that gets you out to 21... Nearly seamless center, and then just pull in the black curtain and give up on the full 23' 6" ... aint nobody gonn miss 1 foot 3" on each side that you masked out, and you have essentially a seamless screen where it counts, and a couple vertical seams way out to the side. The next designer will thank you and will probably just mask the sides on it's next use. Dont know what thread.. probably whatever a seamster/seamstress would normally use so the lycra can still stretch some. That's probably more important than the light transmission properties. Someone at Jo Anne fabric or the like could advise better than me.. Also simple zig zag allows for stretch on a seam.. rather than a straight stitch


Thank you! I was never good at jigsaw puzzles


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## brandtryan (Jun 18, 2021)

*the downstage edge of the stage is represented by the black line that appears, in this image, right in front of the chairs stage right.

I used setalight3D to create my stage, it even let me put in a self-luminescent backdrop which is an actual image from the projection content. The lights are all over the place as I was just goofing around, but it's pretty cool I can see what things will look like or at least roughly.
*after reading this, it almost sounded like an Ad. I'm in no way affiliated with SetALight3D. On their user forums they hadn't ever seen someone use the software to facilitate the lighting design process for the stage.

@RonHebbard when you referenced "side-lighting" and "warm warmer, cool cooler" could you point me to an online resource to learn more about this, or even draw on this screenshot? I'm not quite sure I'm following you. I imagine you're referring to lighting coming from either side of _each _actor - not "warm" light overall stage right, and "cool" overall stage left?

Perhaps I should start a new topic in a more appropriate forum area/topic?


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## macsound (Jun 21, 2021)

brandtryan said:


> View attachment 22019
> 
> 
> *the downstage edge of the stage is represented by the black line that appears, in this image, right in front of the chairs stage right.
> ...


The idea of Warm on one side and Cool on the otherside is almost illustrated by your image. Warm coming from SL, Cool coming from SR.



If you had a whole system of lights, say front lights for 5 sections, that would be 10 total fixtures covering the same 5 sections of your stage. 
If you install slightly bluer gel in the 5 fixtures that are hung 45 degrees up and over from the left and slightly more amber gel in the 5 fixtures from the right. 
Then when you look at a person's face anywhere onstage, the light will be slightly cooler on one half of their face than the other, just like in your render. 

This is commonly used to simulate the direction of the sun and also generally used to add dimension to what could be a flat white frontlight. 
Same goes for highsides, you usually use complimentary colors on the two sides of the stage, adding more dimension than both sides having the same color.


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## brandtryan (Jun 21, 2021)

Thank you for the details, you guys are making me dangerous!


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## jtweigandt (Jun 21, 2021)

I always set up the musicals I light with 5 zones on the FOH and 5 zones on the first electric each covered with 3 elipsoidals.. used to have a Warm Neutral and a Cool.. Now we have Warm, Color changing LED, and Cool. I've seen others come in and use basically 1 color gel for any given scene.. still using the warm neutral or cool to suit their mood, but having the 2 colors from differing angles does lend a richness and depth. You can still lean harder to the warm or cool, but adding that touch of the opposite really makes it all pop. Side lighting for dance if you have the space and geometry also greatly increases depth and interest. But Remember.. I'm just a Veterinarian by trade, with a Theater side hustle.. and no matter what.. some costumer will throw you someone dressed totally in white..


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## brandtryan (Jun 21, 2021)

NO ONE in white lol. Wondered how they did it in cat on a hot tin roof. I recall Big Daddy being in a bright white sear sucker. But that was the movie not sure how it went down on the stage.


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## TimMc (Jun 22, 2021)

brandtryan said:


> NO ONE in white lol. Wondered how they did it in cat on a hot tin roof. I recall Big Daddy being in a bright white sear sucker. But that was the movie not sure how it went down on the stage.


Bright, off-white, seersucker.

TV talking heads wear "white" shirts that are kind of gray next to regular white dress shirt.

I have a friend in TX that painted his studio in a neutral gray (balanced RBG pigment, some formula on line) and he can light it up "chroma key green" with LED fixtures (also on a chart) and it's better than a physical green screen. It takes a lot of green light and a fair bit of space but the evenness is stunning.

Gray. It's your friend. Trust me.


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## RonHebbard (Jun 22, 2021)

I began going grey at seventeen, then soon progressed to white. 
Toodleoo! 
Ron Hebbard


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