Please Read This First
Much to my surprise this has become one of the most popular pages on this site. I would be interested to know if you build a projector screen yourself using this or a similar design. If you send me a picture I can put together a gallery of home built screens. Of course if you have any suggestions for improvements I would be interested to hear them.
Home cinema is a great way to spend piles of money quickly. The projector costs a packet to buy and then more to run (about 10p an hour) and so you really don't want to be shelling even more money out on a projection screen. A custom made projector screen will cost you around £200 at least. I hear you cry foul. Why get a custom made projector screen - can't you just buy one off the shelf. Well yes and no. If you are going for a small image you can buy one off the shelf.
Portable ScreensA portable style projector screen will set you back around £100 to £150 pounds new but to be quite honest if you are going for a picture that small buy a television and save your money. If you are going to project then go for super size! The other problem with portable screens is they are ugly. Not just a little ugly. These things fell out of the ugly tree and hit every branch on the way down. Thy have little spindly sticky-outy legs that trip you up and wobble everytime you look harsly at them.
So I think we have discounted portable screens. What about fixed screens? Now you are talking big bucks. You are in the region of £200 before you even get your over used credit card out and a lot more if you want anything more than a simple white screen.
Why Use a Real Projection Screen?
When you consider the price of a real projector screen you have to admit that it is going to have to be do something pretty fancy to justify it and you wouldn't be wrong. Back in the dark ages, before 1000+ lumen bulbs, projected images weren't up to much. Even in a room that was nearly dark you would barely be able to see the image. To help get round that problem screens were developed with millions of tiny glass lenses imbeded in the cloth. The lens causes the refleced light to be sent back towards the projector and hence the people watching the movie (this of course assumes that you have the standard cinema setup with projector and people in a line). The screens were great. The audience got a bright crisp picture and less light was wasted because it was emitted "off-angle".
Great, I want One of Those Screens
Sure, if you have the money to spare they will improve your viewing experience but I am not sure they are worth it any more. You would probably be better off spending the money on a brighter projector. Even ultra-portable projectors now-a-days can boast 1000 lumnes and fixed projectors are pushing 2000. At around 1500 lumnes you have a projector that gives a watchable picture in full sunlight (our projector is 1200 lumens and the picture is watchable during the day in a north facing room). Since I am far to broke to buy a fancy screen I made my own. The instructions below will hopefully allow you to save some money as well.
Building a Projector Screen
The first thing you have to do is find out how big your screen will have to be. Generally speaking it is harder to get a high screen than a wide screen. This may seem a little odd at first but it is because the height is dictated by the width of the material you use.
The simplest way to find out how large to make you screen is to put the projector where you want it and switch it on. Measure the size of the image on the wall and make you screen that big. This is a sure fire way of making sure you produce a screen that is big enough and also not to big. The alternative method is to project straight onto any wall and take measurements of the picture on maximum zoom and minimum zoom and measure the distance from the projector to the wall. Using some trigonometry you can claculate the size of the projected image for any throw distance.
The choice of material is critical to the whole project. You want something that is heavy, the heavier the better, and not shiny. A shiny material will produce phongs and ruin the viewing experience. A light material will allow to much light through and cause the image to look washed out. We briefly considered a roller blind but you material was too light to be effective.
We chose a material called ticking which is a very heavy cotton. It has a tight herringbone weave which helps stop it stretching. The downside of the herringbone weave is that it produces lines on the material. I was initially a little concerned that they would be visible on the final image but, fortunatly, they aren't. The widest ticking we could get was 152cm which was wider than the measured height of our image which was 135cm. If you shop around you will probably be able to get hold of double width ticking giving you a potential 300cm tall picture. If you can't find double width material and you need more than 150cm (which is a sort of standard) you can join two pieces. I suggest you make joints that are horizontal and make two rather than one. If you are careful you can probably arrange it such that the middle panel will be sufficent for all widescreen presentations and only those in 4:3 will go over the joints.
Unless you are a plumber that is into wood work it's time to visit a DIY store. The basic materials you will need (I am assuming you have the basics like raw plugs, screws and filler) are: A weight for the bottom of the screen to pull it taught, a pole across the top to hold the screen, hooks to hold the bar to the wall, a pully mechanism to raise and lower the screen.
The Pole and Bar
The pole I chose to suspend the screen with was a 2400cm x 35mm wooden dowel. When you choose a pole you have to make sure it can support at least twice its own weight without sagging. One way to do this is to hold it horizonally out from one end. If it bends at all it is not strong enough. You can also use a metal tube and we found some nice looking handrail tubing but it was over twice the price of the dowel (£35 compared to £12 for the dowel) and I like building in wood.
For a weight I initially thought about using lead shot. The problem with that is that over time the lead will rub off on the material and it may clump causing it to pull more in one place than others. I then remembered the metal working section of our local B&Q stocked metal bars. In the end I chose an 200cm x 8mm steel rod for £4. It's not as heavy as lead but it does provide a very even pull on the screen. If you can't find bar like this, or need something a bit heavier, you might be able to pick up steel reinforcing rods at a builders merchant.
Hooks and Runners
Finding hooks that were strong enough and big enough proved to be more difficult that I thought it would. Most hooks were designed for coats and other small items or massive things like ladders. I also didn't fancy putting bare wood directly onto a hook as it was likely to become damaged and look unsightly quickly with repeated raising and lowering of the screen. After walking around B&Q till people looked at us strangely we decided to have a looking in the plumbing section (yes we were desperate). As usual the plumbing section came up trumps.
The dowel, as I mentioned, is 35mm which just so happens to be one of the standard sizes for waste water plumbing (in the UK at least). We decided to get three pipe joining sections and a bag of three clips. The pipe joining sections fit the clips snuggly so there will be no movement in the screen and they slide neatly over the pole. The idea being that they would provide protection to the pole. The total cost of these parts was about £4 but a little modification work was needed.
I've not built this bit yet.
Where to From Here?
You probably want to go to page 2 of the DIY Projector Screen Construction Guide now.