# Rear projection through spandex



## StagePin (Feb 10, 2010)

Ok got a good one for someone.. I am trying to project words from behind a off white spandex sail type . will a small projector about 5-6 feet back work , has anyone done this through spandex yet thanks for any help...


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## Van (Feb 10, 2010)

it works, BUT spandex lets a lot of the light through so you get a real bright spot from the projector. Depending on sight lines some of your audience may feel like they're looking right into the lens. 
Oh SHARYNF ! this is one for you !


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## JohnA (Feb 11, 2010)

FWIW-
I just set up an RSP screen for gobo projection. Initially, the plan was to use spandex; but I wanted to avoid the 'hour glass' type shrinking, so I opted for 
white spinnaker from Rosebrand: 112" White Spinnaker, <span style='color:red'>IFR</span> from Rose Brand

This product allows the gobo images to be seen clearly, but blocks the direct light beam from the intels which are mounted at USL & USR, but pointed toward the DS area.


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## SHARYNF (Feb 11, 2010)

Spandex for rear projection will work BUT you need to place the projector in a position that it is below or above the audience view. Typically I would either place it on the floor or above and just keystone correct. The Problem as Van pointed out is that if you position it "straight on " it is beaming directly into the audience's eyes.

There is a material called Trapeze that has more "density" 
\
http://www.dazian.com/cgi-bin/page.pl?action=end_uses&cat_id=45&group_id=150

In General, it works better with Front Projection.

An alternative solution if you need to project straight on is to troll Ebay and look for the screen surfaces (Rear Projection) from FastFold screens. A TON of these have shown up based on old style multi slide projector shows. This material is grey in color stretches and works well, you can cut out a piece and attach it to your shape. 

Sharyn


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## Kelite (Feb 11, 2010)

SHARYNF said:


> Spandex for rear projection will work BUT you need to place the projector in a position that it is below or above the audience view. Typically I would either place it on the floor or above and just keystone correct. The Problem as Van pointed out is that if you position it "straight on " it is beaming directly into the audience's eyes.
> 
> There is a material called Trapeze that has more "density"
> 
> ...





This is a good choice, depending upon the budget available to you. Trapeze from Dazian worked very well for several Apollo LDI booths over the years, and Dazian was great to work with too! This picture shows a variety of rear-projections, though the booth design is not my favorite...



http://s815.photobucket.com/albums/zz78/Kelite_photos/


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## StagePin (Feb 11, 2010)

*Thanks for the quick replys*

Hey guys thanks for the advice the "sails" are 21' on the left side and 18 ' on the right side and 8' at the top and tapers down to a point on the ground. The top has a lot of surface area to project on and the projected area is about 25' - 30 ' in the air, so sight lines are no problem and I should have no light in the eyes of anybody in the house , I was concerned with punching light through the spandex wondering if a regular small video projector will work ? From what you have said, I should have no problem here so thanks again for the replys and the advice ..this site awesome...!!
I will post pics of the sails soon and let you know how this works out...


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## SHARYNF (Feb 11, 2010)

Projecting thru Spandex is not going to be as bright as a traditional rear projection skin. You will need to determine what other ambient or stage lighting you are using and see if the image will be bright enough

Sharyn


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## ruinexplorer (Feb 12, 2010)

When I was doing hotel AV, we would use spandex for our outdoor poolside movies as it was decent for use and was less expensive to replace if things went wrong. We projected a 9x12 image with a 4500 lumen projector with very good results. We used a larger piece (15x20) for some of the corporate presentations bumping up to 10k lumens and still had a very good image. I completely agree with the projector angle and hot spots. It doesn't have to be off axis by a lot, but enough to avoid the hot spot.


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## museav (Feb 21, 2010)

*Re: Thanks for the quick replys*


StagePin said:


> Ok got a good one for someone.. I am trying to project words from behind a off white spandex sail type . will a small projector about 5-6 feet back work , has anyone done this through spandex yet thanks for any help...




StagePin said:


> Hey guys thanks for the advice the "sails" are 21' on the left side and 18 ' on the right side and 8' at the top and tapers down to a point on the ground. The top has a lot of surface area to project on and the projected area is about 25' - 30 ' in the air, so sight lines are no problem and I should have no light in the eyes of anybody in the house , I was concerned with punching light through the spandex wondering if a regular small video projector will work ?


It appears that you are trying to rear project text that can be read on a triangular shaped spandex 'sail' that is 5' to 6' in front of a wall. I don't think that has really been addressed but can you get an adequate image size with that surface size and shape and the throw distance possible? How far away is the furthest viewer from the images? Is 5' and 6' indeed the room you have to fit a projector behind the 'sail'? What format (4:3, 16:10, 16:9) image are you trying to project? Do you have a projector or any limits on the projector possible? What size text, as in font size in the graphic, do you plan on projecting? Is there masking or anything else around the sails so that someone on one side does not see the projector for the other side?

The point is that the screen being spandex is one aspect but there are other factors that apply to any projection that have to be addressed, such as getting an image that can be read by all viewers. And some things may be interrelated, for example if a very short throw lens is required it has to be on the centerline of the image and may hot spot more.


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