# Daylight Projection



## soundxtreme (Oct 8, 2011)

Good day,

I hope anyone can share some light on the subject 

I am mostly into sound and own a 6m x 4m mobile stage with 6m high scaffolding towers. I am considering to quote for gig next year where a large number of people in the region of 2000 (thumb sucking) will be singing gospel songs but they all need to be able to read the lyrics on two screens in daylight. Due to low budget problems I was told that this does not have to be a display from mars but just acceptable for people to read the lyrics.

I was wondering if anyone have some recommendations for me and is this even possible?
I would love to install two rear view projector screens on the outer sides of my stage scaffolding towers and I am thinking of screens in the region of 3m x 3m. 
Is there any such screens available that is enclosed in the back to keep the area between the screen and the projector dark?
What size of projector should be able to handle this?

I am also looking at entry level.



I will really appreciate anyone's input on this!

Thanks
Dewald


----------



## gcpsoundlight (Oct 8, 2011)

I would be more inclined to look at led panels for an outdoor gig, you would be looking at some hefty projectors otherwise.


----------



## ICEAV (Oct 8, 2011)

Hi Dewald
We distribute a range of projection laminates that could be considered. They are designed to be laminated onto a substrate like say polycarbonate sheet etc The material is 1.5m wide x length required. On wide screen that would make a 1.5m x 2.66m wide screen.You could hang / mount two sheets. We have been experimenting with lamination onto a substrate that could be rolled up. Our holographic screens in a concert can be seen here. For your application you would use our HoloContraBr.

Filo and Peri play ET (Tiesto remix) and B There 4 U (Mat Zo remix) at Webster Hall 2011 - YouTube

The ansi lumen of the projector would need to be at least 10000 ansi at a guess. remember that when you double a screen area you halve the brightness, or halve the size and the brightness will double.

You are after maximum contrast so i would recommend black background and white text.

The other aspect though I would seriously consider in your need is a our flexible led curtain screens designed for graphics and video. On the stage pic you showed you could use 20/25mm pitch.

ICE LED FlexiRoll 20mm Flexible LED Screen - YouTube
If you need to discuss your requirement feel free to contact

Regards
Kevin Andreassend
iceavsales at gmail.com
Holodesk – The Virtual DJ Surface
ICE AV is a innovative communication technology and systems brand.



soundxtreme said:


> Good day,
> 
> I hope anyone can share some light on the subject
> 
> ...


----------



## cpf (Oct 8, 2011)

The best way I can see this working would be LED matrix type signs. There's really no way to keep all light off of the screen without obstructing views, so then you're left with positioning the stage and setting up top & back shields to match the time of day and latitude. What's for sure is that unless you find a projector that can project black, no reasonably priced projector will be able to punch white text through broad daylight with enough contrast to be seen from the back of a group of 2000 people. LED, on the other hand, gets you a lot more lumens for you dollar, but at the price of a not-as-smooth and probably monochrome display.


----------



## soundxtreme (Oct 9, 2011)

Thank you all much appreciated I am taking everyone's advice and will aim my research into this direction!


----------



## museav (Oct 9, 2011)

I agree that LED is going to be a much better option but caution on the use of wide pixel spacing LED curtains for text. It's a function of the LED resolution, the image size and the character size but insufficient resolution could impact the legibility of the characters.

It might also be worth addressing the image size and format. Standard graphics would likely be 4:3, 16:9, 16:10, 15:9 or similar formats rather than the 3m x 3m or 1:1 format size image you noted. This would be especially applicable for projectors which will probably natively be one of formats and creating a different format, e.g. a 3m x 3m image with a 4:3 format projector, could mean not using the full image capability and thus also not the full rated brightness (which assumes using the full image).

The image size also relates to viewing distance. Based on comments from numerous churches that project lyrics, the preferred goal seems to be a maximum viewing distance of 8-10 times the image height. Some churches get much greater ratios but that often requires using larger characters and having less text on the screen at any time. So a 3m high image might be good for a viewing distance of up to around 100', but if you may have people much further away than that you may want to consider using larger text or a larger image.


----------



## ruinexplorer (Oct 11, 2011)

Yes, the rear projection option is possible (basically making a giant projection TV), but the masking would be custom. Since it would take a relatively large area to be covered for the rear projection, you would most likely want to fold your image (just like they do on those TVs) using top-coated mirrors. Even with this option, you would want to make sure that the direct sunlight isn't washing out your image, so you may need the shade canopy in front as well. This will add a bit of difficulty so as not to impair sightlines.


----------



## jbrem003 (Oct 11, 2011)

The best way to go about it if you want to use projectors is to utilize short-throw projectors (you can get them now for about $1k ~ $1.5k apiece) and directly overlap their images. You can set them on top of each other and use the image settings to line up the projection images. You also want to use a screen or projection material that has a high "gain." Gain is the property of how well it reflects light. The closer you can get the projectors to the screen (hence the short throw lenses) and the more light you blast at that surface, the brighter it will be for viewers.

Hope this helps 

-Jon


----------



## soundxtreme (Oct 11, 2011)

Hi Jon,

I like the idea of double projectors a side on a short throw I hope this will enable me to display reasonable clear lyrics in daylight. From what I understand I will not need to tunnel the back of the screen to the projector using this method as I wouldn't know where to start! I was hoping that I can buy custom screens that's closed off already. 

Do you perhaps have any suggestions on what type of entry level projector would be able to handle this then I will see if I can fit that into my budget. I said 3m x 3m screen but that was just thumb sucking I suppose I can even go a bit smaller on the screen size though I am just not sure what would give me the best results!

Thanks again to everyone for your input and suggestions!

Kind Regards
Dewald


----------



## metti (Oct 11, 2011)

Even double stacked, $1.5k projectors short throw or otherwise will not give you the kind if brightness you need in broad daylight. If you are intent on using projectors, you should be looking at 15-20k lumens per screen which is going to cost a lot more than three thousand dollars per side. Digital signage type LED units are probably going to be your best bet.


----------



## museav (Oct 11, 2011)

jbrem003 said:


> The best way to go about it if you want to use projectors is to utilize short-throw projectors (you can get them now for about $1k ~ $1.5k apiece) and directly overlap their images. You can set them on top of each other and use the image settings to line up the projection images. You also want to use a screen or projection material that has a high "gain." Gain is the property of how well it reflects light. The closer you can get the projectors to the screen (hence the short throw lenses) and the more light you blast at that surface, the brighter it will be for viewers.


You need to be careful with 'short throw' projectors as short throw tends to limit where projectors can go and any available lens shift. Two projectors with very short throw lenses might have to both be on axis and thus occupy the same space. And correcting with keystone correction does not work well with stacked projectors. The bottom line is that short throw projectors are often problematic for stacking.

Gain is not how well a screen reflects light, it is more an indication of how it focuses the light that hits the screen back on the axis of the screen. Although modern screen materials can often provide a balance of both gain and viewing angle, typically a higher gain screen is associated with a narrower viewing angle as the screen focuses the light over a narrower area. Conversely, a wide angle screen may reflect light very well but over a wider viewing area, and thus typically has a lower on-axis gain. Back in the days of CRT projectors and high gain fresnel/lenticular rear projection screens you often had a viewing angle that was very narrow and a presenter very far off to the side of the screen might see virtually nothing but a black screen.

Also consider that gain can affect both the projected image and the ambient light. For front projection the screen gain basically affects both the projected and ambient light equally. For rear projection it is almost an inverse relationship, a rear screen that transmits more light from the projection side tends to be less opaque and thus also reflect less ambient light on the audience side. However, when you get into profiled and special surface screens the relationships can get more complex.

You also usually do not want to use short throw lenses in conjunction with high gain screens, or long throw lenses with wide angle screens, as the screen and lens are trying to do almost the opposite thing optically with the light, which can result in image aberrations. A high gain screen with a short throw lens will often exhibit a significant hot spot.

How far the projector is from the screen does not affect the image brightness. But then it is not the image brightness that is the issue for reading text as much as it is the image contrast. And that is where the problem lies as image contrast, the ratio of full white to the minimum black level, for an outdoor application is going to be very dependent on the ambient light hitting the screen. That is one reason why rear screen projection is usually preferred in such applications. With rear screen projection, if you can block all ambient light hitting the rear side of the screen then only a small percentage of the ambient light hitting the audience side is reflected, thus reducing the image black level and from that the image white level required to obtain a usable image contrast ratio.

The problem is that daylight represents a huge ambient light level, so even a small percentage of that represents a significant minimum brightness on the screen. A ran some quick numbers using a 3m x 4m image and daylight with 10% reflectance for the screen and came up with needing something like 39,000 lumens. The most effective way to reduce that number is to reduce the ambient light on the screen.

I do not know of any large screens that have integrated projection spaces, that is usually custom built for the application. You may find a production company that has a complete setup of projector(s), screen and 'projection room' that they will rent.


----------



## Chris15 (Oct 12, 2011)

I think it is salient at this point to remind everyone that the OP is in Africa, not known for great availability of AV in any shape, let alone the kind of complex stuff we're starting to talk about...


----------



## soundxtreme (Oct 12, 2011)

I got a quote to rent two 3m x4m LED screens, virtual 10mm pitch display with scaf structures locally so looks like I will be going this route, thanks again to all.

Regards
Dewald


----------



## museav (Oct 13, 2011)

soundxtreme said:


> I got a quote to rent two 3m x4m LED screens, virtual 10mm pitch display with scaf structures locally so looks like I will be going this route, thanks again to all.


Sounds like a good plan, hope it all goes well!


----------

