# Thread: calculating projection with a Mirror setup

1. ## calculating projection with a Mirror setup

Hi All,

I posted this on another thread, but never got any response, so I am trying again.

I have tried rear projection, but unfortunately did not like the setup and the view.
I tried with shower curtain as a test, but could not get the fold line wrinkles off, perhaps a thin white bedsheet will do, but I am also considering that normal front projection.

I have about 4 ft of space in front of my pit, but would like a large display area.

The projector deals are as follows:

Optoma Gametime 700
throw ratio: 0.72

If I want a 110 in (width) x 130 in (diagonal) x 69 in (height) of screen display area, my projector must be about 6ft 7 in away to get a 16:10 aspect ratio.

1. How do I calculate if I were to use a mirror? Do I divide 6.7/2 = 3.4 ft and place the projector that far away from the mirror so that the image bounces back onto the board to give a 110 in wide display?
2. What kind of mirror can I use? Do I purchase a bigger and wider mirror so that it captures everything the projector is throwing at it?
3. What kind of display material can I buy? Would prepainted white boards be fine as well?

Thanks,

Taufeeq

2. ## Re: calculating projection with a Mirror setup

Hi Taufeeq. Here's a quote from another post, this should help.

Matt Olieman

Originally Posted by Sean Nixon
Hi Jordan

Have you played around with the projector calculator at projectcentral.com? It'll help you decide if a certain projector will work within your dimensions...

http://www.projectorcentral.com/proj...calculator.cfm

As for screen material, have a look at this...

http://www.roberthornedirect.co.uk/Foam-PVC-Sheet/

Sean

3. ## Re: calculating projection with a Mirror setup

Hi Matt,

Thanks so much for the info.

I did check projector central, that is where I got the specs from.

All I need to do is find out how to calculate when there is a mirror in the loop. What size of mirror and the distance between projector and mirror.

I will check for similar display boards here in Canada.

Thanks,

Taufeeq

4. ## Re: calculating projection with a Mirror setup

One thing I experienced, was that I needed a much bigger mirror then what i expected.
You need good mirrors, not the ones from IKEA. Buy at a window shop. They have the quality you need.

A good idea, is to use i.e. a IKEA mirror just for testing so you find the correct size to buy.

You dont need to do much calculation up front. Place your projector as close to the roof you can and as close to the projectionsurface you are able to, and go from there. This way you have a chance to not interfere with your overhead.
See my post in signature for some pics from my mirrored setup.