Our resident Guru, Vicki Frank, is a full bottler on scrim material & other aspects of the effects. Whom I'm sure will respond to this topic shortly & be able to answer all of your questions. Check out her website;-

http://www.studio-productions-inc.com/photo_home.html - http://www.studio-productions-inc.com/photo_home.html

In the mean time I will throw in my thrupence worth [Half a sixpence or tra bit].

I'd imaging you are using a Gymeatre or theatorium for the show. Which will give you more hicups, than you could wave a stick at?

With your back projection, indubitably you will have no upstage space, I have successfully used an ordinary home slide projector, positioned back stage & bounced the image via a mirror. Which will increase it up to by a ratio of about 1:5 times. The mirror bounced the image on to the rear of a Cyclorama & it worked well. However you will have to play about a bit, with the focus adjustment & may even have to muck'bout with the masking & the framing up of projected image. 

With the lighting you will have to be carefully & even use more side [boom &/or ballet barre], balancing the over head ['X' position] & the FOH bar lighting ['Y' Position], by cutting in the profiles [hard edge spots] & barn doors of the Fresnel [soft edge spots] to reduce any wash spill &/or focus them off the screens as much as you can. Thus it will be upto you to fix fart around with the levels, to achieve this, in your design. With th side light you can augment this with back light on to the acting area, to give dimension & definition.

However in your venue this may be drama in it's self, although don't be afraid to use floods & colour from groundrows [strip lights either on the deck ['Z' position], from the sides, mounted on their end from behind the masking legs.

I hope this helps some what?

 

 

 

 

Joe is right on in his comments about upstage space.  Also keep in mind that professional theatrical lights are different than professional architectural lights, with the theatrical lights being easier to get special effects with.

 

1.) The kind of projector for rear projection is one scaled to the environment.  So don't expect to use a conference room projector in a large auditorium.    Use a projector that is sized to get the image size you want in the environment you are using it.  The strength of the projection fades the larger the image and the further the projector is from the screen.  The image also fades with ambient light.  So if you strongly light what is in front of the projection, you might fade the projection itself--just like when the house lights are turned on during a movie viewing.

 

There is nothing particularly special about a rear projector vs. a front projector for the projector itself.

 

2.) But there is something special about the scrim used for rear projection. I suggest using Chameleon scrim (but that is what I sell. See: http://www.studio-productions-inc.com - www.studio-productions-inc.com )  because it has two aspects that are critical to projection quality.  First as opposed to ordinary scrim  (sharkstooth), Chameleon has a denser surface, so you don't lose a lot of projection through the holes in the material weave.  (Sharkstooth when stretched out has holes about the size of those in a screen window, so lots of projection is lost there).  Second, for rear projection a key thing is the transmission of light through the screen as a medium.  Chameleon is thinner and transmits more light, giving it a key advantage in rear projection.  You can see how thin might be better by imagining projecting on a thick wool blanket from behind--not much projection would get through!

 

Chameleon also hangs square allowing this light weight material to be hung in a rectangular shape without heavy seams.  This can be important where you don't have a fly space and are considering building frames.  The negative to building frames with a rear projection is that you see the shadow of the frame silhouetted in the projection--also you see any cross bracing, which is hard not to have in a large screen.  But if you hang a 15' x15' Chameleon scrim it weighs just about a pound.  If you keep the pipe as aluminum on the top and a pVC pipe on the bottom you have something light enough to hang from simple hooks and heavy duty fishing line.  This costs less time to construct than frames, and less money too.

 

Now a note on projection of scenery.  You have several choices... 

 

If you decide that you don't have the upstage space for rear projection, you can front project by moving the horizon of the projection up higher on the screen (thus avoiding shadows of actors downstage). 

 

If you choose to do rear projection you can do full scenic projections (the entire witches castle), or even shadow projections.  Shadow projections can be done of scenery in small scale without a projector.  Light the back wall and use luan (or even cardboard) cut to shape of the witches castle in the distance to be the silhouette.

 

You can also do a reveal of that same scenery in painted form.  Now your painters are only painting a small picture of the witch's castle, or Narnia battle scene, leaving the rest as sky.  That scenery is easy to remove with one stage hand carrying it off.

 

Scenes can be played in silhoutte behind the scrim, or revealed behind the scrim--for example fight scenes may be best to stage in silhoutte to disguise some gore.

 

There are several articles on the Studio Productions, Inc. website about getting these effects and also projection itself.  Take a look at this list and links to articles:  http://www.studio-productions-inc.com/white_papers/wp_home.html - http://www.studio-productions-inc.com/white_papers/wp_home.html

 

Also feel free to contact me through IM if you need more specific advice, or call 800-359-2964 and ask for Susanne.  (In Canada or outside USA call 812-579-5063)

 

 

 

 

Something Susanne touched on was the old Linnebach Effect. Which is the use of a theatre lamp to project a silhouette on to the Us of a back cloth or scrim.

Very easy to do & make up the Lantern. I made up my first one, many eons ago. When I was a wee bloke [Nothing changed there? except for my head - though never grew up anyway!] from a large old biscuit tin, with a bubble [globe] fitted in it & scene cut outs to project the silhouette. I found that I needed to paint the inside of the biscuit tin black. To cut down on reflected light, which cut down on the fuzzy shadows. You could use something similar or a theatre lamp, either Fresnel, Profile or a flood. However you need to remove the lens & reflector to get a fairly sharp image.

You can hire something like the 'Image pro' theatre light fixture & create the image on a computer. But I guess you will have little or no budget to play with in your sandbox.

Another thought is the 'Selecon' Pacific lighting range:-  http://www.seleconlight.com/index.php?option=com_content&task=view&id=370&Itemid=362 - http://www.seleconlight.com/index.php?option=com_content&task=view&id=370&Itemid=362

 

Which are an innovative theatre lamp, made across the ditch from here , in Kiwi Land [NZ], but readily available to hire in USA.

Primarily used for front projection, but can be shuttered & focus to US, away from the performers, as suggested in the post from Sussanne.

The Pacific Lantern has the unquie adavtage of using printed images on plastic/mylar, as GOBO's - wich Selecon term as 'Fergos', after the Ferguson, the bod who delevoped the process, for the lamp.

The lantern disapetes all most all the heat created by the bubble. You can use ordinary GOBO's as well, which might be an option to fiddle  around with.