Okay what ive been seeing so far has been a standing problem, between using a da-lite (ish) screen that brightens the projected image up quite a bit but creates hotspot instead

People try various different paints and fabrics to recover as much brightnes as possible -everything from blackout cloth to various gray-toned fabrics\vinyls to get the desired result

well i have a new idea, ive been searching the forums for a while and i coulnd't find anyone who has thought of it before so i figured i'd make my own thread about it.

What we want is Light reflecting back at us without getting a hotspot right?

well this is just an idea and im still working on it, i dont even have a projector to start with so all i have is
a 500W worklight and some creativity

This is the lamp.





What you see below is -From the left.
*A mirror with foodwrapping-aluminium flattened out with the glossy surface out. tried to get it as flat as possible
*A white standard Paper
*A Mirror with some wrinkled aluminiumfoil flattened out.

The surfaces are all in the hotspot of the 500W lamp in this picture, thus everything looks bright.




Now.. This is when things get interesting, im now standing about 45 degrees towards the different reflective samples and here's when it gets kinda amusing, note that the 500wat lamp is the only lightsource on in the apartment when taking these pictures, so no other light is reflecting on the surfaces.



Looks good eh? Well take a look at this

Basicly im leaning my elbow on my wall, that's how aggressive the angle is, but still! reflects lots of light.

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Not that anyone will view the screen from this angle but still, it prooves the concept.

Now imagen this with a thin, semitransparent clear white matte fabric streached over it, no air between,
im curious about the testresults when i get some fabricsamples and a projector to try it on =) - Then it'll be in a larger scale and the test will be easier to judge.

Well there you have it, A screen based on a flat wooden surface of some sort, sprayglued some wrinkled aluminium foil to it (how coars u want it is up to you, u still get the same effect) and then a fabric of your choise ontop of that, it has to be transparent enough to let through light both in and out, but thick enough to not make the projected image fuzzy due to the dual layers.

well any ideas?

I smell the nobel price

here's a video of the exact same setup as in the pictures, u will see how much light is reflected back at you even if you are in very aggressive angles - it's 12mb widescreen.

Video - Aluminium foil reflecting test. 12mb

Updated with 3 new pictures, i evened out the foil making the surface smoother and the wrinkles alot smaller, they still have the same effect tho, just with a smoother reflecting surface.





this is gonna be very interesting =)

wow.. 73 views and no comments, fellas i kinda need to know if anyone has tried this before and it was all a peice of junk or if it can actually work, please do leave a comment with what you think about all this.

heh, we are all just lurking. I have no idea if it will work or not, but I'm watching and waiting to see if it does.

interesting idea.. I did something similar with metallic spray paint and white cloth (here's a link). The only thing I question is how the image will look with different angles of reflection. Look at this image:
The left shows how light may bounce off your screen, the right shows a the ideal path:

Click to view attachment

I assume it will look like an image projected on a textured wall (ok, but not great). You may find the high points brighter then the low points. Hopefully covering the foil with a cloth would even out the brightness, but you'll just have to try it and see.



Keep up the good work, can't wait to see more pics!!

The problem with this setup is that the image will look "dirty" or "noisy". I did something similar with aluminum paint. I sprayed a piece of polywall, which is a plastic with a rough microsurface (I'm currently using polywall {unpainted} as my screen). It gave good reflectivity, but you could see every flaw, and speckle. It seems the aluminum is so reflective that the difference in brightness by angle on the microbumps is too extreme and noticable.

One idea I hope to try eventually is to coated aluminum foil or aluminum painted surface with a very thin coat of a pyromax type of paint. The idea is that the pyromax type of paint may mitigate the speckles, while still providing good contrast with ambient lighting.

Your idea of using a thin coat of white matt may indeed work. However, you will probably have to experiment to find the right amount of transparency. Too transparent and the image will look "noisy". Not enouf and you simply have a matt white screen.

No, you just left your lamp burning too long near the sofa!!!

Experimentation is what makes this community so much fun. Keep at it until you decide it's the new miracle screen or just a great idea proven wrong.

Interesting inputs, thanks mates

Yes indeed the light reflected back is "noisy" but as the later pictures show u can reduce the wrinklesize quite a bit without loosing too much of the effect so i'll be experimenting a bit, i have talked to a nice woman 70+ in a local shop that deals with cloth and fabrics of different types and she said she has a wide variaty of cheap white\neutral gray cloths with different transparacy and that she'd be happy to cut a heap of test-patches for me to try out =) so i'll do that once i get my projector up and running to do some tests with a real picture -i really think a combination of using small wrinkles and the perfect cloth can give results!

I was thinking about the image you posted xiopod, u're right that the light and colours will be reflecting in different angles but consider the fact that the cloth will be so tight against the foil that it wont have enough space to actually stray to the side and intrude on the colour next to it. - at least not too much.

Well it'll be VERY interesting, cuz if this works it can really be an alternative to those highgain screens u need to open the big wallet to get..

Oh and durachko, it's not the lamp, i noticed later on that i had my stove on and an ovenplate on top of it, must have been that

picked up some patches of fabric today but oh they are sooo small think im gonna haveto go back and ask for larger peices, maybe even pay for them -this sucks, oh well i'll get back with results.

update:

Patches were way to small to give an honest result, looks like im gonna haveto buy a couple patches but that'll haveto wait cuz im running short on money allready this month, gotta eat too hehe

You need to get your priorities straight

For my first screen I picked up a pair of the cheapest white shower curtains I could find at Target, they didn't work too well by themselves because they were so thin. I could see the image almost as well from the back side as the front. I was toying with the idea of gluing some foil behind there to reflect some of the light back, but never got around to it. I found a deal on a decent pull down screen.

My current screen works pretty well at the moment, but if there was a way to get more brightness I'd be all over it. Good luck, and let us know what you find.

well the testpatches i got where stripes of maybe 1x4 inches, and that's way too smal to even judge between the different types of fabric, but once i get my prioritys back in order lol (meaning starving for a month) i'll buy some larger peices of fabric to do some testing, im playing with the thought of a curved screen too, currently working on a 3D model of it.

Start here for your curved screen design....


and here for the foil backing idea. I used mylar...

Good thinking!

Interesting reading, that's one massive thread tho lol

Monday morgning im going back to that sweet old woman and im gonna buy some cloth, i have a couple of experiments i need to do. compare a "good cloth" compareable with the Blackout cloth -compared with a glossy cloth that i stumbled over, it had a matte front side but it's backside was something else it was semi-reflective and it stayed reflective in various angles, so it cant have been very flat, maybe it can give the same effect as the foil but in smaller scale, meaning it is a micro-bumpy surface with a glossy material where every "bump" has a reflective point wich (cuz its rounded) spreads the light even when eyes arent in lightpath, interesting indeed!! i'll look into it. oh btw -i think they can get it in 280cm wide rolls =D=D

I looked at this. "screen goo"

http://www.theaterthings.com/?gclid=CMGgkv...CFR6AWAodPR61pw

It is supposed to be good paint that has a good gain. I have not tried it, but it does look interesting. I would like to know it it works well. Some times this comes up on ebay for less. They have it up to 1.8 gain.

a supposedly high gain low contrast nearly $200 dollar paint mix per quart is likely not what your LL pj needs.

this is half this is half the price and every bit as good/better.



http://www.xfs-screens.com

as far as getting back on the topic of this thread.

what you've done to recreate in a very crude way exactly what happens in a highly metallic concentrated screen mix.

me personally, i would find the highest concentrated silver metallic latex paint that i could find and apply it pure and straight to the substrate of your choice. then i would find a translucent white fabric to stretch over it. you'd probably get more performance mileage out of that visually.

Madsam, dont ya think that's a tad expensive? interesting but still way out of my DIY wallet.

Maxxx, Allso a very interesting alternative to a commercial screen, how about shipping? im in sweden, wonder if that would be a problem.

All in all i just came up with the idea and i wanted to see if it would work, its too early to tell atm but i wanted to try and keep it simple and cheap =) -i'll come back with some results when ive bought some cloth.

I am also following your thread about this ,as I am thinking ahead already and don't want to be without a screen when I fire my pj up .Keep up the good work .

I started down the path of a homebuilt screen, but diverted when I found how inexpensive a real screen is. I bought a Da-Lite Video Spectra 1.5, 96x72 screen for about $160 shipped from "TheFinalClick". It works and looks great (very professional vs. what may have resulted from my home brew screen attempt).

I'm sure being overseas doesn't help the shipping cost, but you may have some local alternative.

all the screens over 100" diagonal that i can find localy are either frickin expensive, we're talking 300usd + for the basic ones clear white no gain. or they're crappy like frick!!.. so a dalite screen would be nice but the shipping would be a laugh..

The texture is a problem. What the high metallic content paint has going for it is its flatness and small texture. If you want wrinkled tinfoil to give you the same performance, what you will have to do, is get it to have a wrinkled texture on a very very fine level. If your wrinkle features are small enough, then to the human eye, all the hot spotting and dark spotting will be averaged out and create a smoother image. I suggest that you try gluing your tinfoil to a very flat board and make the foil itself as flat as you can get it. Then scuff the mirror up with some very very fine sand paper. This will have the effect of creating a rough surface much like your crinkled version but on a smaller scale. I guess the idea here is to get a mirrored surface that reflects 100% (or as much as possible) of the projected light but still scatters the light as diffuser. The only way to do that is to have a rough surface that is made from a reflective material. I don't know if scuffing the aluminum will cause it to absorb more light though. The sanding pattern would make a big difference on appearance, sandblasting would be ideal, the more random the sanded pattern, the better.

You also might try projecting an image to see what kind of image fidelity you get from your different screen materials. A rough estimation can be done by just holding a transparency in between the worklight and the screen. Compare between the white paper and the tinfoil constructions. Again, the finer the wrinkles, the better and more even the image should be.

I just thought of another method you may want to try. Instead of sanding the foil, try sanding the backing. Take a piece of hardboard say (that dark brown, thin and very flat compressed sawdust board) or other flat board, and sand that lightly with your sandpaper. Then when you glue the foil down, press it in really well with a rubber roller or a paint roller (dry of course) and the thin foil will take on the pattern behind it while reducing the depth of the sanded scratches. The reason I suggested hardboard is that it has no grain and you would get a better random pattern. I'm too busy at the moment to try this and the place that I'm living now doesn't allow for me to hook my projector up due to small spaces. I'm experimenting vicariously I hope you try some of these things, I'm really interested to see if they work.

I hate to do all these posts in a row because it doesn't give time for people to feedback but I've had a lot of time on my hands today. I just wanted to say that I found references to a company called Vutec that apparently used special aluminum foil to make a curved screen with a gain of 13! They claim it's the brightest screen in the world. Maybe there is something to this aluminum foil thing. A third idea for surface preparation I had was to take various grades of sand and a rubber roller. Spread the sand over the foil surface and roll tiny sand sized dents into the surface with a roller (doesn't have to be rubber). Different grades of sand would give different feature sizes. Then tip the foil (mounted to a board or something) and brush or blow the sand off.

Very interesting reading, i guess there's many ways to approach this, i fear that the material is allmost too reflective to avoide hotspotting, i still havent finished my projector so the screen project has kinda slowed down lately but it'll be up and running as soon as i have a picture to throw on the wall so i can start experimenting =)

Sanding the tinfoil wouldn't work, it would rip apart like nothing, i ripped it when i wiped it off with a rag hehe

(Sorry for my English)

Hi all

I have already done a screen based on microslabs of aluminum (aluminuim paint) about 2-3 or more
year later

i have done this screen to view strereographic image How :
2 projector, 1 with light vertical polarized 1 with light horizontal polarized
projected to my screen of microlabs of alluminium, due the metallic nature
of the screen the polarization of the reflected images mantains the polarization
so with two polarizers ( you find it from a simple photograph shop ) i can
select images to view the first or the second.

so i have build a 3d glasses to select one image for each eye. As you can imagine
the feeling of the deep dimension ( the real third dimension ) is done by the image
shifting on the two eyes. So i have done 2 diapositive with two photo machine
shifted as the two eyes, of my living room( and not only my living room) with some added
objects to test the 3 Dimensions of some complex object
the results is viewing my living room on a real 3D dimensions from my screen

Now returning to microlabs aluminum screen

Pro:

1) Obviously stereo image or video ( but you need all doubled, video never tested must be
syncronized the cameras and the reproduction of the video so there are additionals problems)
2) Very Very high brigthness and contrast

Bad:

1) Microlabs aluminuim paints are expensive especially on spray ( i have used spray )
2) the screen must be perfect flat, infact micron labs of aliminium create a false diffusive
effects due the semi-random orientations of the micromentrics labs, now false diffusivity effects are
good and isotropy ( for the eye ) into good angles ( i have never measured, but i can measure it)
but this angle of diffusivity is less than for a normal screen so little imperfections are more viewble
than a normal screen. (This the reason because i have used spray to do not create imperfections
, i have not finded a good way to use aluminium paints with paint-brushes withought create imperfections )
3) screen must be fixed as sayed before little imperfections on screen are viewable move the screen, or
deformate it could generete imperfections
4) when you don' t use it, in my opinion is aesthetically ugly, so i think you need a curtain to cover it

Dont you think food wrapping aluminum might be better as a reflector?

probably not

actually, concerning the reflector-issue.. polished aluminium has a highre reflectivity than stainless steel (like the ikea bowls) so covering the DIY reflector with foodwrapping aluminium (if ya manage to get it flat enough) could result in a fair reflector, but i doubt it will reach the effect of the LL pro reflectors or similar mirrorcoated reflectors.

foodwraping alu here in sweden is not mirrorlike tho

Here's a link to a formula for aluminum based screen paint. Don't know anyone that's used it though.

http://www.babousa.org/vtequip.html

Probably is the same paint i have used ( Aluminium Paints with microlabs ) ,
you can find it on most blacksmith shop, i think is simpler

While browsing the net I came across some screen theory (I am going to try this when I get my PJ up & running :

First you need a flat board as your background, this is covered with mylar or some other reflective material (they used to paint it with metallic paints). Obviously, this is just going to bounce everything at you like a mirror, so you cover this with plain net curtain (apparantly nylon is better than cotton), the light bouncing back should cause the fibres in the curtain to "glow" (for want of a better word). Again you would still have a "dazzling" display, so the whole thing is then covered with a thin white cotton sheet stretched taut. You then paint the sheet white (havent found out what paint to use yet) and paint a black border on it. As far as I can ascertain, this is close to how they used to make some of the "silver screens" in the olden days.

Darn - I wish I had bookmarked the link so I could put it on here!!

Like I said, I havent tried it yet - but will as soon as I reach that stage. There is a major drawback with this design though - you cant roll it up as its on a fixed board.

i can tell you allready that idea is creative but from doing my own testing in similar ways our PJ's are WAY too weak when it comes to light-output to first break through a cloth, through the net, then reflect on the mylar and then back through the net and through the cloth, im sorry but with our DIY screens that wont work.

i tried with aluminum foil and a thin white (allmost transparent) peice of cloth used for curtains and allready i saw no gain what so ever compared to a regular white sheet, wich has less hotspotting and certainly gives a more uniform projection.

Having the mylar flat will allso cause hotspotting without a doubt, even if it does make the nylon net to glow it would glow alot more in the middle than in the corners.

im sorry mate.. might work if ya have a decent beamer that puts out 1500-2000 ansi-lumens but our 150-200 ansilumen builds cant cut it. what we need to increase gain is a first surface-material be retro-reflective.

by all means, try it out and get back to us with results but try it in small scale before you pay money to build it big.

Good idea.

I'd like to know too...

I've seen blackout cloth at work. It's ok, but not that great. I know some guys on a budget use paper sheets!
I still have to decide what to use...

Here is a nice link

:

diy screens

Here is an example of painted cloth :

painted cloth

one guy's finding :

guy's

you know,

basically, after reading for a while, all "best" results came from painted -something-. Be it bo cloth, drywall, plywood, etc.

And it's basically a better idea to try and reflect the most of the light before it hits the cloth.

The light hits the cloth, goes through (diminished) is reflected and goes through(diminished again) to be seen.

Whereas if you reflect it directly, it doesn't have to go through two layers of cloth.

Am I wrong here?

Anyways, hope to see some good improvements with your idea. I stil have to find a working lcd ......

cheers!

What if you used some kind of antiglare material similar to what is on most of our LCD screens, and put it in front of the perfectly smooth aluminum?
edit-nevermind, I just tried it and the antiglare is way to transmissive, it barely has any effect, even if a gap is placed between it and the foil. My vote goes for rough sanding a wood substrate, and glueing or somehow attaching the foil so that it follows the contour of the wood.

Hey, I just tried putting a piece of aluminum foil behind a bedsheet in my basement. It does improve the image a bit.

Guess I was wrong.

math, the flatter the reflective surface is the worse it'll get, i bet you could see an improvement cuz you where looking straight at it, but if you put it in the corner, think logicaly, would the light be reflecting back at you? or would it be reflecting out in the room?...

aluminum makes for an insanely bright image in the middle and completely blacked out and crappy brightnes in the corners..

sanding wood and applying aluminum foil to get a structured reflective surface wouldn't work any better, if not worse than the first test i did in this thread with tiny wrinkled aluminum foil - As i said before it looked ok in the middle but the dark corners became even darker, it's too reflective and even if we do get tiny highlights facing the seating-area they are still way too big to create a smooth evenly lit surface, it will be highly noticable when watching a movie and a camera sweeps over a scene, all of a sudden the screen will look static due to the constant "tiny highligts" caused by too large wrinkles.

ive been thinking about retroreflective colour but i havent found anywhere where i can buy it here in sweden, retroreflective colour is used for roadsigns and similar.

--------
Thumbrule. as you said math, we need the light to be reflected from the first surface it hits, and we need to control the reflection somehow, first thing to make sure is that NO light will penetrate the material we're using.

I will be painting my cloth as soon as i get my projector hanging where it should hang (meaning i need to finish the box first lol) otherwise i dont know how large the image will be and i want the screen to PERFECTLY match the projected image.

Nice

I hope the painted cloth will do well.

I just tried it in the corners and indeed, to have a good image, we'd need a spherical shaped of aluminum... But then, you'd only be able to see it from one spot only.

No good for now.

Still, it was fun doing it.

Right now, everything is better than that yellow wall of mine. Although with the reflector in place, it's still a big wow factor.

I can't wait to finally get a screen in that basement!

I was reading through this thread and it reminded me of the Winsor & Newton Iridescent Medium. It is a clear liquid with tiny metallic flakes that look like tiny pieces of aluminum foil. I have tried applying a clear coat containing these metallic flakes and found that most of the flakes lined up parallel to the surface. Ideally they would have a more random orientation. I think the Behr Matte Polyurethane dries quite thin so I will try using the Behr Faux Glaze as a carrier in hopes that it will create a thicker film with greater variations in the flake orientation. I then face the same issue of diffusing the light. In my case I will try a second clear coat containing pearl flakes. Basically the same idea just a different implementation.

The biggest problem I see with the wrinkled foil is density. There needs to be many wrinkles in the space of one pixel. That leads me to wonder if a sandblasted aluminum surface may be better. There is a type of sandblasting grit that is tiny glass beads. This would be the ideal grit to sandblast the aluminum surface. The result is more like a ball-peaned surface. Regular sand grit would make the surface too matte and that would reduce the reflective efficiency.

sandblasting foodwrapping-aluminium would tear it to shreds, it breaks for nothing, if that werent the case i would give that a shot since i believe it could work, but i still think using something THAT reflective will result in hotspotting even if we actually do get a defussing surface

Main thing to achive is to get the light to reflect on the very first surface it hits on the screen, and that it does not let ANY of the light through. souch as a hardboard painted white or something in that order.

Im still gonna experiment with painted cloth to achive at least some texture defussing the light -maybe that would enable me to use a paint with a higher gloss than completely matte? that would give some gain.

Dunno.... I'm wondering about using some glossy type of surface ??

I would have to be perfectly even to produce good results.

I'll be checking.

no no, using a flat glossy surface will generate hotspots like hell! avoid it if possible.

I wasn't thinking of sandblasting tin foil. I was thinking more of a sheet of aluminum or stainless steel. Or a thin layer of metallic foil bonded to a backing of some sort.

I have wondered about sandblasting the face of a 1/16" thick acrylic mirror.

I know people who have used artist's canvas stretched over a frame. They painted it and added satin polyurethane to the paint get just the right amount of sheen. They felt the texture of the cloth was helpfull in diffusing the light so they could use more gloss than on a smooth surface.

Yep as i said, ive read a lil about it and i will experiment with it, i'll start matte and gradually go glossier, gloss=gain if defused =)

What paint products are you going to use?

How will you vary the sheen?

i will start by using a matte white ceeling-paint, they are VERY matte and bright white compared to many others that are kinda creamy in comparission, they exist in different gloss-levels and all i will start off rather matte and will do a test-board of about 50cm x 50cm and try a glossier version of the same colour.