[littlebuzz]

This is my first attempt at a window projection. While waiting for my projector to arrive, I'm considering my screen options.

The most popular material for window projections is the white shower curtain liner. Unfortunately, I have a streetlight across from me that lights up the shower curtain.

I was wondering if the grey mesh fabric folks are using for scrim would work for a rear projection window display.

What do you think?

 

[Chewbacca]

I just finished building a rear projection screen for my crypt doorway. I tried several different materials but all the fabrics and even a commercial rear projection material showed a nasty hot spot from the projector which has to be directly behind the screen. The shower curtain completely hid the hotspot but, like you, I found it very visible under any ambient light. The solution I came up with was to stretch a thin black spandex like material over the front of the shower curtain. This kept the hot spot hiding of the shower curtain and made the front of the screen black. The only issue I've had is the brightness setting of the projector needed to be bumped up a little and the image was a little more diffuse than I'd like but it looks fine from the distance people will be viewing it from.

 

[J-Man]

I would stick with the cheap WHITE shower curtain. The street light probably won't be a problem once your projector is going. The down side to grey mesh (or any mesh) is seeing the projector beam through it. If your window is on the second floor this usually isn't a problem, 1st floor can be an issue.

 

[JCO]

Using mesh is very effective for hologram projections but it carries very restrictive conditions with it. Will the hot spot be visible? Will bleed-through spoil the illusion? There's no point in doing it with the lights off in the room, you'll get a horrible background glow even if you can't see the hot spot. Hologram is my preferred presentation for window projections but it's not always possible.

I couldn't find it just now but there used to be a video on YouTube of a guy who was playing one of the old Hallowindow videos on a shower curtain at dusk and complaining about the same thing, how the screen was visible in ambient light. He put some kind of black scrim in front of the shower curtain as Chewbacca suggested (I can't remember what it was; spandex or tulle or chiffon or what) but it noticeably helped, even seemed to sharpen the image up a little. Definitely worth a try.

 

[JCO]

edit - double post

 

[JCO]

Here it is. There's actually no before and after comparison, but it looks like dusk, nowhere near full dark, and you can see how deep the black is. Unfortunately, he doesn't name the material.

https://www.youtube.com/watch?v=e_z4ukcCbCQ

 

[Krismusfur]

Using mesh is very effective for hologram projections but it carries very restrictive conditions with it. Will the hot spot be visible? Will bleed-through spoil the illusion? There's no point in doing it with the lights off in the room, you'll get a horrible background glow even if you can't see the hot spot. Hologram is my preferred presentation for window projections but it's not always possible.

I couldn't find it just now but there used to be a video on YouTube of a guy who was playing one of the old Hallowindow videos on a shower curtain at dusk and complaining about the same thing, how the screen was visible in ambient light. He put some kind of black scrim in front of the shower curtain as Chewbacca suggested (I can't remember what it was; spandex or tulle or chiffon or what) but it noticeably helped, even seemed to sharpen the image up a little. Definitely worth a try.

I just came across that video earlier today! Its on the Hallowindow blog
http://hallowindow.blogspot.com/2009/06/improving-contrast-with-black-scrim.html

 

[JCO]

LOL, I beat you by one minute! But yeah, that's it.

 

[Krismusfur]

LOL, I beat you by one minute! But yeah, that's it.

Dang!!! I'll need to be quicker next time

 

[littlebuzz]

JCO, adding a layer of black scrim might be the ticket.

It's a 1st floor window. 84" tall, but the bottom 16" are blocked by bushes, so I don't think I'll have any issues with the hot spot.

 

[JCO]

I just started doing projections last year and when I was projecting against a solid white vinyl shower curtain liner there was absolutely no hot spot visible even though I took no steps to hide it. The projector was straight behind the screen at waist height, I didn't bother to set it out of the spectators' line of sight - no problem with hot spotting at all. I think hot spotting starts to become an issue as the material gets thinner or more translucent, as in frosted (not solid) liners, mesh, etc.

 

[JCO]

I put together a side-by-side comparison video, projecting onto a shower curtain, with and without scrim. I tried to use a variety of video clips and varying ambient light conditions, from just after sunset to full dark. In some conditions the scrim really REALLY improves the effect; in other conditions not so much. Hope this helps.

https://www.youtube.com/watch?v=NUQJX7aXddY

 

[6-paq]

This is great JCO! I appreciate the time and effort you placed in making this comparison video. I'm still deciding on whether to go with a holographic effect or just go to the white shower curtain. If I go with the curtain, my projector is pretty bright, so I would need a scrim overtop.

 

[littlebuzz]

Excellent description and comparison JCO.
My Epson projector arrived yesterday so I'm off to pick up some materials this afternoon. I plan to stop by Jo-ann's to get some chiffon and Walmart to pick up the white plastic. While at Walmart, I will also buy a black plastic table cover. Those table covers are thin, and I'm betting my projector can shine right through it. If it works at all I'll post my own comparison video.

 

[Icepick]

Excellent description and comparison JCO.
My Epson projector arrived yesterday so I'm off to pick up some materials this afternoon. I plan to stop by Jo-ann's to get some chiffon and Walmart to pick up the white plastic. While at Walmart, I will also buy a black plastic table cover. Those table covers are thin, and I'm betting my projector can shine right through it. If it works at all I'll post my own comparison video.

I can tell you now, it will show through the black. Even my cheap 80-100 lumen projectors make it through the thin black ones.

 

[6-paq]

Excellent description and comparison JCO.
My Epson projector arrived yesterday so I'm off to pick up some materials this afternoon. I plan to stop by Jo-ann's to get some chiffon and Walmart to pick up the white plastic. While at Walmart, I will also buy a black plastic table cover. Those table covers are thin, and I'm betting my projector can shine right through it. If it works at all I'll post my own comparison video.

I'm interested to see a video. How many lumens is your Epson?

 

[littlebuzz]

2600
It's the PowerLite 821p

 

[6-paq]

2600
It's the PowerLite 821p

Similar lumens to my epson 730hd. I have 3000 lumens in normal and 2100 in eco mode. I am finding it to be very bright and I'm running in eco.

 

[littlebuzz]

Well you might have luck with the black plastic table cloth but I wouldn't bet on it.

My results so far...
White shower curtain: Even on low, I couldn't achieve a black background.
3.5mil black plastic: Too dark, could barely make out image.
Black plastic table cover: Also too dark.

Tonight I will do the black chiffon over the white shower curtain