Charles Lohr's Blog: June 2010

I purchased a HD20 Optoma 1080p projector and fell in love with using it against the wall in my old dorm room. Recently, though, there have been more and more cases where I needed to use the projector somewhere where a wall was unavailable.

We ended up doing rock band in a number of unusual places, we we needed a solution.

This prompted the purchase of a sheet from target. This was fraught with problems. The sheet allowed too much light through from behind. When there wasn't much light, light would pass through the sheet, bounce off of whatever was behind it and then come back through the sheet causing "echoes" of sorts. The king size bed sheet technique failed miserably.

This first picture shows the echo effect, you can see it around the Pin Panic and ACK in Attack.

One fun thing that happened was we were able to play though the sheet. NOTE: This is actually TWO sheets. These king size sheets are ridiculously translucent.

Now that I have gotten around to it, I went to Jo Ann Fabrics and bought 1.5" of every white fabric that I thought would be reasonable.

These cloths include (in order of increasing appeal after tests)

Wool Felt - 37" Wide, $9.99/yd, 2.0 oz for 3 sqft, capable of making a [37"x65"]; [75" or 6.25' diag.]; [17 sqft] screen @ $19 and 11 oz. - Fail immediately, produced a "lumpy" surface in terms of brightness.
Polyester Felt - 72" Wide, $4.99/yd, 1.5 oz for 3 sqft, capable of making a [72"x128"]; [146" or 12.2' diag]; [64 sqft] screen @ $18 and 32 oz. - Fail immediately, produced a "lumpy" surface in terms of brightness.
Polyester Fleece - 62" Wide, $7.99/yd, 3.0 oz for 3 sqft, capable of making a [62"x110"]; [126" or 10.5' diag]; [47.3 sqft] screen @ $25 and 47 oz. - Fail immediately, produced a blurry picture.
Cotton Denim - 56" Wide, $9.99/yd, 3.5 oz for 3 sqft, capable of making a [56"x99"]; [114" or 9.5' diag]; [37.5 sqft] screen @ $28 and 44 oz. - Fail after a bit of consideration, produced unusual patterns because the ridges in the denim interacted with the pixels. It also wrinkles very easily.

Now, we move on to the winners.

Polyester Pleather - 54" Wide, $8.99/yd, 2.0 oz for 3sqft, capable of making a [54"x96"]; [110" or 9.1' diag]; [36 sqft] screen @ $24 and 24 oz. - One side is blurry, the other is very shiny but sharp. This unfortunately allows the projector to reflect back in your face, so there's bright spots. This is usable for rear or front projection, but would not be my first choice. Does not allow much light through but you can still see it on the other side. This means echoes will be very minor. If this is used for rear projection, it will eat a lot of the light but will not have a bright spot where the projector is.
Target 30% Cotton 70% Polyester - 56" Wide, $6.99/yd, 2.0 oz for 3 sqft, capable of making a [56"x99"]; [114" or 9.5' diag]; [37.5 sqft] screen @ $20 and 25 oz. - Probably best material if you still wanted rear projection to be possible. Both sides are relatively good and very similar. Picture quality almost as good as #1 and #2. This allows you to do rear projection. Front projection will have a worse echo problem then the pleather. I am considering this, since I may want to do rear projection. Also this will have a bright spot where the projector is.
Multipurpose Cloth - 54" Wide, $19.99/yd, 4.5 oz for 3sqft, capable of making a [54"x96"]; [110" or 9.1' diag]; [36 sqft] screen @ $54 and 54 oz. - Completely opaque, no chance of echo. Sharp picture, almost the same as blackout cloth. Prohibitively expensive and very heavy. This could double as a thick blanket in an emergency. :-p
***Black Out Cloth (70% Polyester, 30% Cotton) - 54" Wide, $5.99/yd, 3.5 oz for 3sqft, capable of making a [54"x96"]; [110" or 9.1' diag]; [36 sqft] screen @ $16 and 42 oz. - Opaque, nice, sharp picture. Very similar to multipurpose cloth. Fabric does not breathe, would not use as a blanket. Does not seem very easy to clean either. BUT! It's CHEAP, OPAQUE and not too heavy! This is what I will be building my screen out of. There's a lot of guides that go about ways of doing this. If I find a particularly innovative way, I may post it.

I took a number of pictures to compare.

You can see the pictures over at http://cnlohr.net/Pics/ProjectorTestPreview/

Some interesting pics are: [Poly Felt, Denim, Fleece, Target, Pleather, Wool Felt]